AU2011250713B2 - A gaming machine and method - Google Patents

Abstract

Abstract The present invention provides a gaming machine (1), comprising: a display (7) for displaying a visible array (8) and a plurality of first game symbols (9) in the visible array (8), and a controller (4) for controlling the display of the first game symbols in the visible array (8), wherein, in response to a trigger event, the controller (4) replaces one or more selected first game symbols (9) with one or more replacement game symbols (10, 17, 18) from an array (11) hidden from the display (7). A method is also provided. Figure 3 1,3 12a 120 12c 12d 12e Fig. 2 ------------ 10 Jo 2 13' =12a3 12 12c 12d 12e -~---'-----oig.3

Description

- 1 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: Ainsworth Game Technology Limited Actual Inventors: Peter Scott Clarebrough and Pairatch Paotrakul Address for Service is: SHELSTON IP 60 Margaret Street Telephone No: (02) 9777 1111 SYDNEY NSW 2000 Facsimile No. (02) 9241 4666 CCN: 3710000352 Attorney Code: SW Invention Title: A gaming machine and method Details of Associated Provisional Application Nos. 2010905027 dated 10 Nov 2010 and 2010905595 dated 22 December 2010 The following statement is a full description of this invention, including the best method of performing it known to us: File: 68373AUP00 -2 Title of Invention A GAMING MACHINE AND METHOD Field of the Invention [0001] The present invention relates to a gaming machine and in particular to an electronic gaming machine. [0002] The invention has been developed primarily for use as an electronic gaming machine and will be described hereinafter by reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use. Background of the Invention [0003] The following discussion of the prior art is intended to present the invention in an appropriate technical context and allow its advantages to be properly appreciated. Unless clearly indicated to the contrary, however, reference to any prior art in this specification should not be construed as an express or implied admission that such art is widely known or forms part of common general knowledge in the field. [0004] Conventional gaming machines typically involve awarding prizes to a player according to predetermined combinations of game symbols that appear on an array of game squares displayed on a screen, typically organised into three rows and five columns (a 5x3 array). Other arrays, such as a 3x3 or 4x3, may be used. Each gaming machine randomly selects the game symbols that appear on the array, each column of the array being a "reel". In an electronic gaming machine, the reels are visibly spun on the screen to simulate a physical reel of a traditional gaming machine. [0005] Electronic gaming machines are also more versatile in presenting game information, varying the probabilities for a player to win a prize and varying the type of game that is played. Bonus or "feature" games may also be provided in addition to the base or main game. Despite these enhancements, the focus of such electronic gaming machines tends to remain with the play of a single game shown on the screen display.

-3 [0006] Consequently, it is difficult to retain player interest because there is no apparent incentive for the player to continue playing the same gaming machine (traditional or electronic), since the award of the prize is random in nature and there is little differentiation between gaming machines in terms of the games that are played. [0007] It is an object of the present invention to overcome or substantially ameliorate one or more of the disadvantages of prior art, or at least to provide a useful alternative. [0008] It is an object of the invention in at least one preferred form to provide a gaming machine and a method for controlling a gaming machine that encourages player interest. Summary of the Invention [0009] The invention provides an electronic gaming machine, comprising: a display for displaying a visible array and a plurality of first game symbols in the visible array, and a controller for controlling the display of the first game symbols in the visible array, wherein, in response to a trigger event, the controller replaces two or more selected first game symbols with the same replacement game symbol from an array hidden from the display. [0010] Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to". [0011] Preferably, the same replacement game symbol can be selected randomly or in a predetermined order from the hidden array. Alternatively, the two or more selected first game symbols are replaced by different replacement game symbols. In this embodiment, the replacement game symbols can be selected randomly or in a predetermined order from the hidden array. [0012] Preferably, the replacement game symbol is selected on the basis of the trigger event. For example, in one embodiment, the trigger event involves the display of a special game symbol and the replacement game symbol is selected to be the same as the special game symbol. Alternatively, in another embodiment, the replacement game symbol is selected randomly or in a predetermined order from the hidden array.

-4 [0013] Preferably, the visible array forms a substantially geometrical shape having a plurality of game positions. Preferably, the geometrical shape comprises a rectangular or square shape. Preferably, the visible array is arranged in rows and columns of game positions. [0014] Preferably, the trigger event comprises the display of at least one special game symbol on the visible array. More preferably, the trigger event comprises the display of a special game symbol at one or more predefined locations on the visible array. In one embodiment, the one or more predefined locations comprise one or more game positions in one or more columns of the visible array. In a particularly preferred embodiment, the columns are predefined on the visible array. In another embodiment, the one or more predefined locations comprise one or more game positions in one or more rows of the visible array. In a further embodiment, the one or more predefined locations comprise game positions in a combination of at least one row and at least one column. [0015] Preferably, the controller selects the two or more selected first game symbols according to a relationship with the special game symbol. More preferably, the two or more selected first game symbols have a spatial relationship with the special game symbol. In one embodiment, the two or more selected first game symbols share or are displayed in the same column as the special game symbol displayed on the visible array. In another embodiment, the two or more selected first game symbols are adjacent to the special game symbol. In a further embodiment, the controller selects all the first game symbols displayed in the same column as the special game symbol displayed on the visible array. In yet another embodiment, the controller selects all the first game symbols displayed in the same row as the special game symbol displayed on the visible array. In some embodiments, the visible array comprises a plurality of columns and said predefined locations comprise game positions in a first column and a second column, the selected first game symbols in said first column each being replaced by a first replacement game symbol and the selected game symbols in said second column each being replaced by a second replacement game symbol, said first replacement game symbol being different to said second replacement game symbol. [0016] Preferably, the replacement game symbol selected from the hidden array is the special game symbol. [0017] Preferably, the hidden array comprises at least one column of the replacement game symbols. More preferably, the hidden array comprises a column of replacement game -5 symbols for each predefined column in the visible array, said predefined columns being less than the total number of columns in the visible array. In another embodiment, the hidden array comprises a column of replacement game symbols for each column in the visible array. [0018] Preferably, the replacement game symbols increase the likelihood of a predetermined winning combination being displayed on the visible array. The specification also describes a method for controlling a gaming machine having a display for displaying a visible array and a plurality of first game symbols in the visible array and a controller for controlling the display of the first game symbols in the visible array, the method comprising the steps of displaying the visible array, randomly displaying the first game symbols on the visible array, and, in response to a trigger event, selecting two or more first game symbols on the visible array and replacing the selected first game symbols with the same replacement game symbol from an array hidden from the display. [0019] Preferably, the replacing step comprises selecting the replacement game symbol randomly or in a predetermined order from the hidden array. Alternatively, the replacing step comprises replacing two or more selected first game symbols with different replacement game symbols. In this embodiment, the replacing step comprises selecting the replacement game symbols randomly or in a predetermined order from the hidden array. [0020] In one embodiment, the replacing step comprises selecting the replacement game symbol on the basis of the trigger event. For example, where the trigger event involves the display of a special game symbol, the replacing step comprises selecting the same replacement game symbol to be the same as the special game symbol. In another embodiment, the replacing step comprises selecting the same replacement game symbol randomly or in a predetermined order from the hidden array. In a further embodiment, the replacing step comprises selecting the special game symbol as the same replacement game symbol selected from the hidden array. [0021] Preferably, the selecting step comprises selecting the two or more first game symbols according to a relationship with the special game symbol. More preferably, the selecting step comprises selecting first game symbols that have a spatial relationship with the special game symbol. In one embodiment, the selecting step comprises selecting two or more first game symbols that share or are displayed in the same column as the special game symbol in the visible array. In another embodiment, the selecting step comprises selecting two or more selected first game symbols adjacent to the special game symbol.

-6 [0022] Preferably, the method further comprises providing the hidden array with at least one column of replacement game symbols. In one embodiment, the providing step comprises providing the hidden array with a column of replacement game symbols for each predefined column in the visible array, said predefined columns being less than the number of columns in the visible array. For example, where the special symbol can only appear in three predefined columns in the visible array, the hidden array has three columns of replacement game symbols, one column for each predefined column. In another embodiment, the providing step comprises providing the hidden array with a column of replacement game symbols for each column in the visible array. Again, for example, if the visible array has five columns, the hidden array has five columns, one for each column of the visible array. Likewise, if the visible array has four columns, the hidden array has four columns, one for each column of the visible array. [0023] It will be appreciated by one skilled in the art that the hidden array may have rows instead of columns that correspond to the predefined number or total number of columns or reels in the visible array. Also, the hidden array may have rows corresponding to a predefined number of rows or the total number of rows in the visible array, in a similar manner as discussed in the preceding paragraph. For example, where the special symbol can only appear in three predefined rows in the visible array, the hidden array has three rows of replacement game symbols, one row for each predefined row. [0024] The invention is preferably implemented in both a base game and a bonus game of the gaming machine. That is, in both the base game and the bonus game, a trigger event causes the one or more selected first game symbols to be replaced by one or more replacement symbols from a hidden array. Where the bonus game employs other game symbols different to the first game symbols, the trigger event causes one or more selected game symbols displayed during the bonus game to be replaced by one or more replacement symbols from the hidden array. Also, it will be appreciated that the invention can be limited to only the base game or only the bonus game. The invention could also be extended to multiple bonus games. [0025] In one particular embodiment, the gaming machine provides one or more bonus games in response to a bonus trigger event. In one embodiment, the bonus trigger event is a predetermined number of second game symbols appearing on the visible array. Preferably, the predetermined number is three second game symbols. In the bonus game, the visible -7 array displays randomly selected first game symbols, special game symbols and bonus game symbols. Where the bonus game symbol appears on the visible array, the bonus game symbol is preferably replaced by a replacement game symbol randomly selected from the hidden array. Where more than one bonus game symbol appears on the visible array, the bonus symbol is preferably replaced by the same replacement game symbol randomly selected from the hidden array. However, the bonus symbols could also be replaced by one or more replacement game symbols from the hidden array. In a variation of this embodiment, the replacement game symbol is selected according to a predetermined order from the hidden array. [0026] In another embodiment, the bonus trigger event is a predetermined number of bonus game symbols appearing of the visible array. In one preferred form, the predetermined number is three bonus game symbols. In the bonus game, the visible array displays randomly selected first game symbols, bonus game symbols and one or more wild card symbols. [0027] Preferably, the replacement game symbols comprise any one of the first game symbols, the second game symbols, the special game symbols, the bonus game symbols and the wild card symbols. Alternatively, the replacement game symbols comprise game symbols that are different to the first game symbols. In one embodiment, the special game symbols increase the likelihood of a predetermined winning combination being displayed on the visible array. [0028] Preferably, the first game symbols, the second game symbols, the special game symbols, the bonus game symbols and the wild card symbols include graphical images of numbers, playing cards, letters, fruit, animals and people. In one embodiment, the images are partially or fully animated. [0029] Preferably, the gaming machine enters a winning game state when one or more predetermined winning combinations of first game symbols appear on the visible array. Preferably, the predetermined winning combinations comprise a predetermined number of first game symbols appearing in predefined locations in the visible array. In one embodiment, the predetermined number of first game symbols include from three up to five first game symbols. In another preferred embodiment, the predefined locations comprise rows in the visible array. In another embodiment, the predefined locations comprise five game positions in the visible array, wherein at least one game position is selected from each column of the visible array.

-8 [0030] Preferably, the gaming machine also enters a winning game state when one or more predetermined winning combinations of the replacement game symbols and the first game symbols are displayed on the visible array. In one preferred form, the replacement game symbols increase the amount of the prize awarded on the predetermined combination of replacement game symbols and the first game symbols. [0031] It is also preferred that the gaming machine enters a winning game state when a predetermined number of second game symbols are displayed on the visible array. In one embodiment, the predetermined number of second game symbols include from three to five symbols. Brief Description of the Drawings [0032] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: [0033] Figure 1 is a perspective view of a gaming machine according to a first embodiment of the invention; [0034] Figures 2 and 3 are schematic drawings illustrating a game; [0035] Figures 4 to 13 are schematic drawings illustrating the first embodiment of the invention; [0036] Figures 14 to 21 are schematic drawings illustrating a second embodiment of the invention; and [0037] Figures 22 to 27 are schematic drawings illustrating a third embodiment of the invention. Preferred Embodiments of the Invention [0038] Referring to Figure 1, a gaming machine 1 according to a first embodiment of the invention includes a cabinet 2, a console 3 and an internal controller 4. The console 3 includes vending slots 5 for receiving monetary bets and a plurality of buttons 6 for actuation by a player. A video screen 7 displays a visible array 8 and a plurality of first game symbols 9 in the form of playing card symbols on the visible array to play a main or base game on the gaming -9 machine. The controller 4 controls the display of the first game symbols 9 on the visible array 8 and, in response to a trigger event, replaces one or more selected first game symbols 9 with one or more replacement game symbols 10 from an array 11 hidden from the display 7. In this embodiment the hidden array 11 is separate from the visible array. [0039] Referring to Figure 2, the visible array 8 is arranged in five columns or "reels" 12 and three rows 13 to form a standard 5x3 array well known in the gaming industry. It will be appreciated by one skilled in the art that other arrays could be used, such as 3x3, 4x3, 5x5, 4x4, etc. The 5x3 visible array 8 defines predetermined game positions or "squares" 14. The visible array 8 is arranged so that a player can select one or more predetermined "paylines" 15 defined around the array, which correspond to combinations of the game positions 13. The paylines generally comprise at least one game position 14 from each reel or column 12. The number of paylines 15 that can be selected depends on the amount of the monetary bet for playing the game. [0040] When a game is played, the controller 4 causes the reels 12 to appear to visibly rotate on the visible array 8 and randomly display the playing card symbols 9 in each game square 14. After the reels 12 stop spinning, the controller 4 determines whether there are any predetermined winning combinations of the playing card symbols 9 appearing in any player selected paylines 15, such as a "full house", "straight" or "flush". If so, the gaming machine 1 enters a winning game state and awards a prize according to the displayed predetermined winning combination. [0041] In this game, the appearance of a special game symbol in the form of a joker card 16 is a trigger event that causes the controller 4 to replace one or more playing card symbols 9 with one or more replacement game symbols 10 from the hidden array 11, as best shown in Figures 2 and 3. The hidden array 11 is in the form of a single reel with a plurality of replacement game symbols 10 including playing card symbols 9, one or more bonus game symbols 17 or a wild card symbol 18. The bonus game symbols 17 include a multiplier symbol that increase the amount of any awarded prize by the multiplier (in this case, the "x2" symbol doubles the amount) and a free games symbol that confers free games to the player without having to make a monetary bet (in this case, the "10 Free Games" symbol grants ten free games). It will be appreciated that the amount of the multiplier and the free games symbols is not limited by the illustrated symbols and can include other amounts, such as "x3", "x4", "8 -10 Free Games" and "15 Free Games". In this game, the replacement game symbols 10 are randomly selected from the hidden array 11. [0042] The controller 4 selects the playing card symbols 9 according to a relationship with the joker card symbol 16. In this game, the playing card symbols 9 that share the same reel 12 as the joker card symbol 15 are selected for replacement. As best shown in Figure 2, the joker card symbol 16 has appeared in the fourth reel 12d, and so the other playing card symbols 9 in the fourth reel 12d are replaced by the bonus game symbol 17 "10 Free Games" and the playing card symbol Qv. Also, the joker card symbol 15 is replaced by a wild card symbol 18 "JOKER'S WILD". The wild card symbol 18 can be any playing card value to maximise the possible predetermined winning combinations for the player selected paylines 15. Thus, if the player had selected the three paylines 15 corresponding to the three rows 13 of the visible array 8, the gaming machine 1 would enter a winning game state as the first row shows 3 queen cards (2 queen card symbols and the "JOKER'S WILD" symbol) and the third row shows a "straight" poker hand comprising 9-10-J-Q-K playing cards. In addition, a bonus feature of ten free games would be awarded from the display of the "10 Free Games" symbol in the second row. However, it will be appreciated that due to the random selection of replacement game symbols 10 from the hidden array 11, not every replacement will result in a predetermined winning combination. [0043] A first embodiment of the invention is illustrated in Figures 4 to 12, where corresponding features have been given the same reference numerals. In this embodiment, a game called "Red Robin" is played on the gaming machine 1. In the Red Robin game, the visible array 8 displays first game symbols 9 in the form of playing card symbols 20, picture symbols 21 and a special game symbol 22 in the form of a red robin, as best shown in Figure 4. [0044] The playing card symbols 20 include ace, king, queen, jack, ten and nine cards while the picture symbols 21 include a frog, a bird bath, a butterfly, a nest and a rose. There is a hierarchy for both the playing card symbols 20 and the picture symbols 21, where combinations of certain game symbols confer a prize of greater value than combinations of other game symbols. For example, a combination of the ace playing card symbols has a greater value than the same combination of the queen playing card symbols. Likewise, combinations of the bird bath symbol may be allocated a greater value than combinations of -11 the frog symbol. It will be appreciated that the hierarchies for the playing card symbols 20 and the picture symbols 21 can be readily changed by the controller 4. [0045] Also shown on the screen 7 adjacent to the visible array 8 are various game indicators 23 for showing information relating to the game being played. For example, indicator 23a shows the number of paylines selected by the player, indicator 23b shows the amount of credit on the game, indicator 23c shows the amount bet, indicator 23d shows the amount won and indicator 23d displays game information relating to the state of play. An example of the number of possible paylines 15 for the Red Robin game is illustrated in Figure 5. [0046] The embodiment operates in a similar manner as the game of Figures 2 and 3, with the reels 12a to 12e being spun to randomly display the playing card symbols 20, picture symbols 21 and the special game symbol 22. In the Red Robin game, a trigger event occurs when the special game symbol 22 (red robin) is displayed in any of the second, third and fourth reels 12b to 12d. Thus, if the red robin symbol 22 were to appear in the first reel 12a or the fifth reel 12e, this would not cause the trigger event. [0047] The trigger event causes the game symbols 24 in the same reel as the special game symbol 22 to be selected for replacement by the controller 4. In this embodiment, the selected game symbols 24 are replaced by the special game symbol 22 that is taken from the hidden array 11; that is, the red robin symbol, as best shown in Figure 6. In this case, the red robin symbol 22, and hence the replacement game symbol, acts as a "wild card" and increases the likelihood of the visible array 8 showing one of the predetermined winning combinations and thus place the gaming machine into a winning game state. [0048] The visible array 8 may also display a "scatter" symbol 25 in the form of a cuckoo clock picture symbol, as best shown in Figure 7. The gaming machine 1 provides a bonus game when a predetermined number of the scatter symbols appear anywhere on the visible array 8. In this embodiment, three cuckoo clock symbols trigger the bonus game, which takes the form of ten "free" games that are played on the visible array 8 without requiring the player to place a monetary bet. The reels 12a to 12e are spun each time and a prize is awarded for each predetermined winning combination that appears on the visible array 8. The playing card symbols 20, picture symbols 21, red robin symbol 22 and a bonus symbol in the form of a shield 26 can be displayed during play of the bonus game. As best shown in Figure 8, the -12 third and fourth reels 12c and 12d each display three bonus shield symbols after a spin of a free game on the visible array 8. [0049] The controller 4 replaces each bonus symbol with the same replacement game symbol 10 randomly selected from the hidden array 11, as best shown in Figure 9. This significantly increases the likelihood of a predetermined winning combination being displayed on the visible array 8. In Figure 9, the shield symbols 26 have been replaced by the same replacement queen symbols 10, thus increasing the chances of obtaining a winning combination of 3, 4 or 5 queen symbols in a player selected payline 15. [0050] Another free game played in the bonus game is illustrated in Figures 10 and 11, where corresponding features have been given the same reference numerals. In this free game, the bonus shield symbols 26 again appear in the third and fourth reels 12c and 12d, as best shown in Figure 9. In this example, the replacement game symbol 10 randomly selected from the hidden array 11 is the red robin symbol 22, as best shown in Figure 11. The red robin symbol 22 again acts as a wild card to confer the optimal winning combinations of game symbols to the player. [0051] A further free game played in the bonus game is illustrated in Figures 12 and 13, where corresponding features have been given the same reference numerals. In this free game, the bonus shield symbols 26 appear in one game position 14 in the second reel 12b and in each game position 14 in the third and fourth reels 12c and 12d, as best shown in Figure 12. In this example, the replacement game symbol 10 randomly selected from the hidden array 11 is the ten playing card symbol, as best shown in Figure 13. The presence of multiple ten playing card symbols increases the chances of winning combinations of game symbols being displayed on the visible array 8, which in this case are 3, 4 and 5 of a kind. [0052] A second embodiment of the invention is illustrated in Figures 14 to 21, where corresponding features have been given the same reference numerals. In this embodiment, a game called "Rapid Strike" is played on the gaming machine 1. In the Rapid Strike game, the visible array 8 displays first game symbols 9 in the form of playing card symbols 20, picture symbols 31, scatter game symbols 32, 33 and 34, and special game symbol in the form of a green dollar sign symbol 35. The playing card symbols 20 include ace, king, queen, jack, ten and nine cards while the picture symbols 21 include a triple "7" logo, cherries, bells, a diamond and gold bars. The scatter symbols include a red strike symbol 32, a purple strike symbol 33 and a "free games" symbol 34.

-13 [0053] As with the first embodiment, in the second embodiment the screen 7 adjacent to the visible array 8 has various game indicators 23 for showing information relating to the game being played, such as indicator 23a showing the number of paylines selected by the player, indicator 23b showing the amount of credit on the game, indicator 23c showing the amount bet, indicator 23d showing the amount won and indicator 23d displaying game information relating to the state of play. Also, the number of possible paylines 15 for the Rapid Strike game is the same as the number of paylines for the Red Robin game as illustrated in Figure 5. [0054] The second embodiment of Figure 13 operates in a similar manner as the first embodiment, with the reels 12a to 12e being spun to randomly display the playing card symbols 20, picture symbols 31, scatter game symbols 32 to 34 and the green dollar symbol 35. The gaming machine 1 enters a winning game state for any predetermined winning combination of playing card symbols 20 or picture symbols 31. As with the first embodiment, there is a hierarchy for both the playing card symbols 20 and the picture symbols 31 where combinations of certain game symbols confer a prize of greater value than combinations of other game symbols. These hierarchies for the playing card symbols 20 and the picture symbols 31 can be readily changed by the controller 4. Where a predetermined number of red strike symbols 32 or the purple strike symbols 33 appear on the visible array 8, the gaming machine 1 is placed into a winning game state where a bonus prize is awarded, as best shown in Figure 15. The predetermined number of red strike symbols 32 or the purple strike symbols 33 is from 6 up to 9. The greater the number of red strike symbols 32 or purple strike symbols 33 that are displayed on the visible array 8, the higher the bonus prize that is awarded. In Figure 15, the lowest bonus prize has been awarded as there are six red strike symbols appearing the second reel 12b and the fourth reel 12d. These bonus prizes are awarded in addition to any other predetermined winning combinations of the playing card symbols 20 and picture symbols 31. However, in this embodiment a threshold bet must be made by the player to activate the award of bonus prizes. The predetermined number and the threshold bet can be readily increased or decreased by the gaming machine controller 4. [0055] As best shown in Figure 15, the appearance of green dollar symbols 35 in the reels 12a to 12e on the visible array 8 is a trigger event that causes the green dollar symbols 35 to be selected for replacement by the controller 4. In this embodiment, the selected green dollar symbols 35 are replaced by the same replacement game symbol 10 that is randomly selected from the scatter symbols 32, 33 and 34 in the hidden array 11. That is, only one of the red strike symbol 32, the purple strike symbol 33 and the "free games" symbol 34 is used to -14 replace each green dollar symbol 35. In the example of Figure 15, the green dollar symbols 35 on the first reel 12a, third reel 12c and fifth reel 12e of the visible array 8 are replaced by purple strike symbols 33 from left to right, as best shown by the sequence of Figures 16 to 18. It will be appreciated that the green dollar symbols 35 can be replaced at the same time or in a different sequence to that shown in Figures 16 to 18. [0056] Where the replacement game symbol 10 is either the red strike symbol 32 or the purple strike symbol 33, there is an increased likelihood of the player winning a bonus prize if there are other red strike symbols 32 or purple strike symbols 33 on the reels 12a to 12e of the visible array 8. [0057] In another example, the green dollar symbols 35 on the first reel 12a, third reel 12c and fifth reel 12e of the visible array 8 are replaced by "free games" symbols 34 from left to right, as best shown by the sequence of Figures 19 to 21. Again, the green dollar symbols 35 can be replaced at the same time or in a different sequence to that shown. As described above, the green dollar symbols 35 have been selected for replacement by the controller 4, which has randomly selected the "free games" symbol 34 from the hidden array 11. [0058] Where the replacement game symbol 10 is the "free games" symbol 34, the gaming machine 1 provides a bonus game when a predetermined number of the "free games" symbols 34 appear. In this embodiment, three "free games" symbols 34 trigger the bonus game, as best shown in Figure 21. The bonus game takes the form of six, seven, eight, nine or ten free games that are randomly selected by the controller 4 for play on the visible array 8. The player is not required to place a monetary bet to play these free games. The allocation of the number of free games is accompanied by an animation to increase the interest and anticipation of the player for the bonus game. [0059] In each free game, the reels 12a to 12e are spun each time and a prize is awarded for each predetermined winning combination that appears on the visible array 8. The playing card symbols 20, picture symbols 31, "free games" symbol 34 and a wild card symbol in the form of a gold dollar symbol 36 can be displayed during play of the bonus game. Predetermined winning combinations of playing card symbols 20 and picture symbols 31 are calculated after each spin. Where a wild card gold dollar symbol is displayed after a spin of a free game on the visible array 8, it increases the likelihood of the visible array 8 showing one of the predetermined winning combinations and thus places the gaming machine 1 into a winning -15 game state by taking the value of any playing card symbol 20 or picture symbol 31 that obtains the highest winning combination in a particular payline 15. [0060] A third embodiment of the invention is illustrated in Figures 22 to 27, where corresponding features have been given the same reference numerals. In this embodiment, a game called "Mustang Money" is played on the gaming machine 1. In the Mustang Money game, the visible array 8 displays first game symbols 9 in the form of playing card symbols 20, picture symbols 41, scatter game symbol 42, and special game symbols 43 and 44. The playing card symbols 20 include ace, king, queen, jack, ten and nine cards while the picture symbols 41 include a dollar, a canyon, an eagle, a cactus and gold bars. The scatter symbol is in the form of a "Mustang Money" symbol 42 and the special game symbols are in the form of a horse symbol 43 and a coin symbol 44. [0061] As with the first and second embodiments, in the third embodiment the screen 7 adjacent to the visible array 8 has various game indicators 23 for showing information relating to the game being played, such as indicator 23a showing the number of paylines selected by the player, indicator 23b showing the amount of credit on the game, indicator 23c showing the amount bet, indicator 23d showing the amount won and indicator 23d displaying game information relating to the state of play. The number of possible paylines 15 for the Mustang Money game is greater than the number of paylines for the Red Robin and Rapid Strike games, amounting to 100 lines, as illustrated in Figure 23. [0062] The third embodiment of Figure 22 operates in a similar manner as the first and second embodiments, with the reels 12a to 12e being spun to randomly display the playing card symbols 20, picture symbols 41, scatter Mustang Money game symbol 42, the horse symbol 43 and the coin symbol 44. The gaming machine 1 enters a winning game state for any predetermined winning combination of playing card symbols 20 or picture symbols 41. Again, there is a hierarchy for both the playing card symbols 20 and the picture symbols 41 where combinations of certain game symbols confer a prize of greater value than combinations of other game symbols. For example, combinations of the dollar symbol may be allocated a greater value than combinations of the cactus symbol. Also, the hierarchies for the playing card symbols 20 and the picture symbols 41 can be readily changed by the controller 4. [0063] The horse symbol 43 and coin symbol 44 act as a wild card symbol to take the value of any of the card symbols 20 or picture symbols 41 to increase the likelihood of the visible -16 array 8 showing one of the predetermined winning combinations and thus place the gaming machine into a winning game state. [0064] Where three Mustang Money symbols 42 appear on the visible array 8, the gaming machine 1 is placed into a winning game state, as best shown in Figure 22. In addition, the gaming machine 1 provides a bonus game, which takes the form of ten "free" games that are played on the visible array 8 without requiring the player to place a monetary bet. While three Mustang Money symbols 42 are required to trigger the bonus game in this embodiment, the predetermined number of scatter symbols to trigger the bonus game can be varied as desired. The bonus games are awarded in addition to any other predetermined winning combinations of the playing card symbols 20, picture symbols 31 and the horse symbol 43. [0065] In the bonus game, the reels 12a to 12e are spun each time and a prize is awarded for each predetermined winning combination that appears on the visible array 8. The playing card symbols 20, picture symbols 41, the Mustang Money symbol 42, the horse symbol 43 and the coin symbol 44 can be displayed during play of the bonus game. However, the Mustang Money symbol 42 now acts as a wild card symbol like the horse symbol 43. Also, the horse symbol 43 can only appear in the third or middle reel 12c and the coin symbol 44 can only appear on the second and fourth reels 12b and 12d, respectively. As best shown in Figure 24, the second and fourth reels 12b and 12d each display three coin symbols 44 after a spin of a free game on the visible array 8. Of course, three coin symbols 44 do not always appear in the second and fourth reels 12b and 12d, respectively. For example, only one or two coin symbols 44 may appear in either the second reel 12b or fourth reel 12d. [0066] In addition, whenever coin symbols 44 appear on the visible array, each coin symbol 44 is selected for replacement by the controller 4 with the same replacement game symbol 10 randomly selected from the hidden array 11. Where more than one coin symbol 44 appears on different reels 12, a different replacement game symbol 1 is selected for each reel. As best shown in Figure 25, the coin symbols 44 in the second reel 12b have been replaced by an "X2" replacement game symbol 45, whereas the coin symbols 44 in the fourth reel 12d have been replaced by an "X5" replacement game symbol 46. [0067] The X2 and X5 replacement game symbols 45, 46 have two functions in the bonus game. Firstly, the X2 and X5 replacement game symbols 45, 46 act as wild card symbols in determining whether the visible array 8 displays a winning predetermined combination of game symbols. Secondly, the X2 and X5 replacement game symbols 45, 46 are multipliers in the -17 same way as the "x2" symbol 17 in the second embodiment. That is, each multiplier symbol increases the amount of any prize awarded on a predetermined winning combination displayed on the visible array 8. The X2 symbol 45 doubles the amount of any awarded prize and the X5 symbol 46 quintuples (or multiplies by 5) the amount of any awarded prize. It will be appreciated that other multiplier replacement game symbols can be used, such as "Xl", "X3", "X4" and so forth. The dual function of the replacement game symbols 45 and 46 enhances the enjoyment of the bonus game for the player. [0068] In a particularly preferred form, the replacement game symbols for the second reel 12b are randomly selected from the X1 and X2 multiplier symbols, while the replacement game symbols for the fourth reel 12d are randomly selected from the X1 and X5 multiplier symbols. Again, the replacement game symbols need not be limited in this manner in other forms of this fourth embodiment. [0069] Another free game played in the bonus game is illustrated in Figures 26 and 27, where corresponding features have been given the same reference numerals. In this free game, the bonus coin symbols 44 have only appeared in the second reels 12b, as best shown in Figure 26. In this example, the replacement game symbol 10 randomly selected from the hidden array 11 is the X2 multiplier 45, as best shown in Figure 27. [0070] In the first, second and third embodiments, the hidden array 11 comprises a single reel. However, it will be appreciated that the hidden array can have more than one column or reel. In one variation of the second embodiment, there is a dedicated reel in the hidden array 11 for each reel 12a, 12b, 12c, 12d and 12e on the visible array 8. That is, the hidden array 11 has five reels, one for each reel 12a, 12b, 12c, 12d and 12e on the visible array 8. Moreover, the hidden array may have a separate reel or reels for the main or base game that have different game symbols than the reels for the bonus game. Also, the hidden array may have rows instead of columns that correspond to the predefined number or total number of columns or reels in the visible array, or corresponding to a predefined number of rows or the total number of rows in the visible array. [0071] Furthermore, the use of a replacement game symbol in each of the described embodiments can be equally applied to a base game, bonus game, multiple bonus games or any combination thereof. For example, in both the base game and the bonus game, a trigger event causes the two or more selected first game symbols to be replaced by the same replacement symbol from a hidden array. Where the bonus game employs other game -18 symbols different to the first game symbols, the trigger event causes two or more selected game symbols displayed during the bonus game to be replaced by the same replacement symbol from the hidden array. In another preferred embodiment, multiple bonus games are provided, where a trigger event in a bonus game activates additional bonus games that in turn trigger more bonus games, the replacement game symbol from the hidden array being used in one, some or all of the bonus games. [0072] The disclosed embodiments represent basic configurations for the gaming machine 1 and it will be recognised that other variations are possible within this basic configuration. For example, the visible array 8 need not be limited to a 5x3 array, but can include a larger or smaller arrays, such as a 5x5 array or a single row of five game positions. Moreover, while the preferred embodiments have arrays that are rectangular in shape, it will be appreciated that the visible array can displayed with any other shape, such as a square, an oblong, a triangle, a circle, a diamond, an oval or any other polygonal shape. [0073] Likewise, the hidden array 11 need not be limited to a single reel, but can be arranged with more reels in a similar manner to the visible array 8. Also, the controller can selectively choose replacement game symbols from the hidden array 11, based on the trigger event, as well as choose replacement game symbols in a predetermined order instead of a random selection. In other preferred forms, the same replacement game symbol need not replace the game symbols appearing on the same reel or even row, but different replacement game symbols can be used to replace game symbols on the same reel or row. [0074] By providing a hidden array of game symbols for replacing the game symbols appearing on the visible array, the player's anticipation and excitement is heightened as he or she watches the game symbols be replaced by the replacement game symbols that may increase his or her chances of achieving a winning combination of game symbols or a winning combination of higher value. Thus, it is more likely that a player will retain interest in continuing to play the same gaming machine. Furthermore, since the controller controls operation of the visible array and the hidden array, the invention can be readily implemented to existing gaming machines and other gaming systems. In all these respects, the invention represents a practical and commercially significant improvement over the prior art.

-19 [0075] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Claims (21)

1. An electronic gaming machine, comprising: a display for displaying a visible array and a plurality of first game symbols in the visible array, and a controller for controlling the display of the first game symbols in the visible array, wherein, in response to a trigger event, the controller replaces two or more selected first game symbols with the same replacement game symbol from an array hidden from the display.

2. The electronic gaming machine of claim 1, wherein the same replacement game symbol is selected on the basis of the trigger event.

3. The electronic gaming machine of claim 1, wherein the same replacement game symbol is selected randomly from the hidden array.

4. The electronic gaming machine of claim 1, wherein the same replacement game symbol is selected in a predetermined order from the hidden array.

5. The electronic gaming machine of any one of the preceding claims, wherein the replacement of the two or more selected first game symbols is visually indicated on the visible array.

6. The electronic gaming machine of any one of the preceding claims, wherein the trigger event comprises a display of a special game symbol at one or more predefined locations on the visible array.

7. The electronic gaming machine of claim 6, wherein the one or more predefined locations comprise one or more game positions in one or more columns of the visible array.

8. The electronic gaming machine of claim 6, wherein the one or more predefined locations comprise one or more game positions in one or more rows of the visible array.

9. The electronic gaming machine of any one of claims 6 to 8, wherein the visible array comprises one or more columns of game positions and a play of the game commences by the controller making the one or more columns appear to visually rotate on the display, the special -21 game symbols being initially displayed with randomly selected first game symbols on the visible array when the one or more columns appear to visually stop and then are replaced with the same replacement symbol.

10. The electronic gaming machine of any one of claims 6 to 9, wherein the controller selects the two or more selected first game symbols according to a relationship with the special game symbol.

11. The electronic gaming machine of claim 10, wherein the two or more selected first game symbols have a spatial relationship with the special game symbol.

12. The electronic gaming machine of claim 10, wherein the visible array comprises one or more columns of game positions and the relationship comprises the two or more selected first game symbols being displayed in the same column as the special game symbol displayed on the visible array.

13. The electronic gaming machine of claim 10, wherein the relationship comprises the two or more selected first game symbols being displayed adjacent to the special game symbol.

14. The electronic gaming machine any one of claims 6 to 9, wherein the visible array comprises one or more columns of game positions and the controller selects all the first game symbols displayed in the same column as the special game symbol displayed on the visible array.

15. The electronic gaming machine any one of claims 6 to 9, wherein the visible array comprises one or more rows of game positions and the controller selects all the first game symbols displayed in the same row as the special game symbol displayed on the visible array.

16. The electronic gaming machine of any one of claims 6 to 9, wherein said visible array comprises a plurality of columns and wherein said predefined locations comprise game positions in a first column and a second column, the selected first game symbols in said first column each being replaced by a first replacement game symbol and the selected game symbols in said second column each being replaced by a second replacement game symbol, said first replacement game symbol being different to said second replacement game symbol. - 22

17. The electronic gaming machine of any one of claims 6 to 16, wherein the replacement game symbol selected from the hidden array is the special game symbol.

18. The electronic gaming machine of any one of the preceding claims, wherein the hidden array comprises at least one column of the replacement game symbols.

19. The electronic gaming machine of claim 18, wherein the hidden array comprises a column of replacement game symbols for each predefined column in the visible array, said predefined columns being less than the total number of columns in the visible array.

20. The electronic gaming machine of claim 18, wherein the hidden array comprises a column of replacement game symbols for each column in the visible array.

21. The electronic gaming machine of any one of the preceding games, wherein the replacement game symbols increase the likelihood of a predetermined winning combination being displayed on the visible array.