COMPLETE PECIFICATION Standard Patent App icant InventJ- ite The following Statenent We a fulldscizont fc; etan In ui~j. e otmehdforn fozlqItkon ote Gamig machine 'with adjustable return to player Field of the invention R Te peetivtinenrlyrlesto gain n ho and nawsof SWmNg. W uh h icae of gambling at gmn eushscm nrae optto 1c between aning yvnues t o otialrershare of the toAl gambling spend. Gainn venue operators have therefore continousy lokd otnwvaitin and types of" games in coder to attract both new and return csoest hi eus in response to this need. suppliers gmngdvie adsytmshveatepedt i p-ro'viCe the sought after -aiy We Sd ~~sta opywth he reevt regulatons in the jurisicton of the gainn eueoxrto.Supleso gamning deviewteefr arc fae ihrsrcin ntetpesofainsan nn machies tat ae alowable, booth in tenns of the prevailing creation and in terms ot providng a return on "xeunn"o tegiigvneoeaos in. aHiOW. suppliers need to control the c-Ost o.'fnaufcui ann.mcie incidig ostsinvolved in the design of' games providedb gcin acies n cotin dessal !nC Fctt exaitin 0 a trrnin.7venus whin Te samejurisdiction requd e i--a~ am utwt 10 Tat is aragd opovd- pa&fa game of chanc in which the Play of the gamne Ouch that a total number ot pis Of the reels conforms to an overal staistca retun to "~-"~ im'Qnef aplualiy of, dtert stat6isti ai rtu to plye attrbue toth 15 respective oane of the spins of the reels.
wherein if a first of the statistical return to player attributes is located to a respective one of the spins of the reels the respective one of the spins of the raes would be associated with a first statistical return that is less than the overall statistical return to player attribute, and if a second of the statistical return to player attributes is allocated 5 to a respective one of the spins of the reels the respectWve one of the spins of the reels would be associated with a second statistical return that is greater than the overall statistical return to player attribute, and wherein the method includes allocating the one of the plurality of different statistical return to player attributes to the respective one of the spins based on a weighted random selection process so as to result in the total number of spins of the reels conforming to the overall statistical return to player attribute. (Tne outcome of the game may be the award of a certain umber of free gante plays of the game and wherein the irst pay characteristic is the award of a first number of free 1 games on the occurrence of that outcome and the second pay caeristicis the award of a second number of free games on the occurrence of hat outcome, The alocaton may be made before commencement of the game play. c The allocation may be nade after it has been determine hat said outcomewillocur The first pay characteristic may be the randomrselection of symbol frafi rst syniol set andhe second pay characteristic isthe random selection of symbols from a second symbol set' The game is a spinning reel game and the first symbol set is a first reel and a second symbol set is a second reel and the weighted random selection process includes selecting the first or the second reel for use in the game. The weighted selection process may select between only the first reel and the second reel Alternatively, the weighted selection process may select between three or more alrematiVe reels. The game. maybe a spinning re! game and the First svmbIA set is a first rnel strip, as portion of a combined reel of the game and a second symbol set is a second reel stip portion of the combined reel. wherein the first and second wed strip portions consist of 4 alterate implementations of the game with different statistical returns, and wherein the number of first and second reel strip portions are provided in proportion to result in said overall statistical return so that the weighted ran dom selection process includes selecting the stopping position of the combined reel. S The first pay characteristic and the second pay characteristic may be selected from the group comprising: alternative symbol sets in the game provided in proportion so as to result in the overall statistical return; alternative awards in the game provided in proportion so as to result in the overall statistical return: attemnative trigger event probabdities provided n proportion so as to result in the overall statistical retur; and 10 alternative awar-d multipliers, provided in proportion so as to result in the overall statistical return The first and second pay characteristics may be of the same type anddffer only as to their magnitude. The first and second pay characteristics may operate only in a base game of the game 15 The game may include a feature game. The first and second pay characteristics may operate ol in a feature game ofthe game, The aocation fora game lay may be independent of the aItocation for any other game 20 In the weighted random selection process the probabity of selecting the first pay characteristic may be calculated according to The formtua: p1i= S - R2)/(R - R2) and the probability of selecting the second pay characteristic may be calculated according to the formula: p)2 =z# -p1) where: p1 - the probability of selecting the firAst pay characteristic set in the weighted random selection process: S p= the probabiit of eletng the second pay characteristic in the weighted random Sp- the narbbyl Wo eleiates selection process; 8S the overall statistical return to player value; RI the statistical return associated with the first pay chacit; R2 = the statistical return associated with the second pay chaacerstic; and 10 RI -<-S <IC In a scondspect he present inventan prod "a method C re a ganing mac-ine thts arranged to pride a Olay of a gane of chancein tc p1-t the gan~ameise a puaiy of di .- ctsp'i -b of red's the ganr- 1 ng 0 mrachne aangd. operate Sch that a tot al iCY on unes of hde rees conforns to a ms.tii rerun to plaVer attrbue g gaming machine provided with a puraoit *s osts IN ha asta t set iaasecondsmo settheissmboxset having atst associatedretum to player value and the secondsynbolset avin a scono 20 ess Han the " s'titpiai etur to player attrIibut and the second associaeed return to players is greater thn the overall staticalrturto plar attre wherein each symbol set incudes synabols arranged lnto a pluraity of' reel Stlo to he'wly of reel stro coresponding r'ciel o tepuatyorelstrip. display positions and wherein the method neudS 'iet deefenllnga game ur.t 'wh ni)4 v outconm. ocatin:g one or a phrran iy different statistical return to player atnrbrutes to the ethod includes selecting between the ofurlitvof symbol sets for display on the displaywhein the selection is a weighted random selection process thatresuts in the totA numnitr of spins ofMth reels eonin" to me overall statisical retun to e iay ot gaming gbivinth svnmois from the selected symbol set or display on the display, The ganving machine may be a reel type gaming machine and t display includes a plurality of reel strip display positions. ard wherein each symbol se t includes symbols arranged into a plurity of reel strips, the plurality of reel snips corresponding arespectiy to the plurality of reel strip display positions.
6 The first symbol set aid second symbol set may differ from each other ny in respect of a single reel sthp. The plurality of symbol sets may differ from each other by at least one characteristic selected from the group of a symbol type and a bonus associated with the set of 5 symbols, The weighted random section process the probability of selecting the first synbo! set may be calculated according to the formula: p1 - (S - R2)(RI R2) and the robabilty ofseectng theecond symbol set may be calculated according to 1 0 the forofa: p2 (1I where P1 = the probability of selecting the et symbol set n the weighted random selection oracess; 15 p2 The probability of selectng the second symbol set in the weightediandom selection process; S the overall statistical return to pyervalue' Ri the first associated retum o player value R2 the second associated return to player value; and 20 RI %S MR2. According to a further aspect the invention broadly resides i instructions executable by a gamne controller to implement the method as described in 4 he preceding paragraphs and to such instructions when stored in a storage medium readable by the game conroler 7 n a third aspect the present invention provides a gaming machine that provides a game based on a wager, the gaming machine comprising a user interfacein communication with a game controller the game controlle adapted to implment the method as described above, 5 According to a further aspect the hvent'on broadly relates to a data signal carrying instructions and/or data executable to implemenit the method as described above. Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings T0 Brief descrIption of the drawings Figure t shows diagrammatica a view of a gaming nsol suab fr implementing the present invention. Figure 2: showsa block diagram of gaming machne suitable for implementing the present inventin. 15 Fioure 3: shows a ok diagram of componen~s of the mohe machine represented in iqre 2. Figure: shows diagrammaticaly a network gaming system sutabe for implementing the present ivention. Figure: shows a depicont odiments of 20 the oresen vention. Figure shows a de iosmple ame screeruse wi emoie the oeetivnin 8 Figure 8: shows a flow diagram of a process performed in accordance with an embodiment of the present invention. Detailed description of the embodiments ln Figure 1 of the accompanying drawings, one example of a gaming console that is 5 suitable to implement the present invention is generally referenced by arrow 114, The gaming console 114 includes two displays 106A, 1063 on one or both of which is displayed representations of a game that can be played by a player and a bank of buttons 107A and/or a touch screen 1073 to enable a player to play the game, The displays 106 may be video display units, such as a cathode ray tube screen device, a 10 liquid crystal display, plasma screen, any other suitable video display uni or the visible portion of an electromechanical device. The display 106B may display artwork, including for example, pay tables and details of bonus awards and other information or images re ating IC the game. In alternative gaming consoles the display 1068 may be omitted, p Hreplaced by a static display 15 A credit input including a coin input 1 IA and/or bill collector 110B allows a player to provide credit for wagering and a coin output 111 is provided for cast. payouts from the gaming console 114. A card and/or ticket reader 108 and a printer 109 may be provided to provide player tracking, cashless geie play or other gaming and non-gaming related functions. 20 Figure 2 shows a block diagram of a gaming machine, generally referenced by arrow 100, suitable for implementing the present invention. The gaming machine 100 may include the gaming console 114 shown in Figure 1 and accordingly like reference numerals have been used to describe like components in Figures 1 and 2, The gaming machine 100 includes a game controler 101, which n the illustrated 25 example includes a computational device 102, which may be a microprocessor, mcrocontroiier, programnmabe logic device or other suitable device, instructions and data to control operation of the computational device 102 are stored in a memory 103, wich is in data communication with, or forms pan' of, the computational device 102, Typicaly, the gaming machine 100 wil include both volatile and non-volatiie memory and more than one of each type of memory, with such memories being collectively represented by the memory 103. The instructions to cause the game controller 101 to implement the present invention will be stored in the memory 103. The instructions and 5 data for controlling operation of the computational device 102 may be store ed on a computer readable medium from which they are loaded into the gaming machine memory 103, The instructions and data may be conveyed to the gaming machine by means of a data signal in a transmission channel Examples of such tranrnission channels include network connections, the Intemet or an intranet and wireless 10 communication charnnels. The game contro0er 101 may incude hardware credit meters 104 for the purposes of regulatory compliance and also ince an inputtoutput (/O) interface 105 for communicatng with the peripheral devices of the gaming machine 100. The input/output interface 105 and/or the peripheral devices may be intelligent devices with heir own 1A memory for instructions and data. in the example shown in Fgure 2, the peripheral devices that communicate with the controller are the displays 106, bank of buttons/touch screen 107, the card and/or ticket reader 10$, the printer 109, a bi acceptor and/or coin input 110 and a coin output 111 Additional devices may be included as pat of the gaming machine 100, or devices 20 omitted aseqidred for the specific implementation, The bank of buttons 107A and/br touch screen 17 tether with one or both of the displays 106 may provide a user interface 115 through which the gaming machine 100 and player communicate. If a card/ticket reader 108 is provided, This may also form part of the user interface 115. 25 in addition, the gaming machine 100 may include a communications interface, for example a network card 112. The network card 112, may for example, send status information, accounting information or other information to a central controller, server or database and receive data or commands from the central controller, server or database, The network card 112 may also enable communication with a central player account, 10 allowing cashless gaming. One or more of the peripheral devices, for example the card/bcket reader 108 may be able to communicate directly with the network card 112. The network card 112 and the 1/O interface 105 may be suitably implemented as a single machine communications interface. 5 The game controller 101 may also include a random number generator 11.3 which generates a series of random numbers that are used by the computational device 102 to determine the outcomes of games played on the gaming machine 100, The game controller 101 may have distributed hardware and software components that communicate with each other directly or through a network or other communication 10 channel The game controller 101 may also be located in cart or in is entirety remote from the user interface 115. Also, the computational device 102 may comprise a plurality of devices, which may be local or remote from each other. Instructions and data for controlling the operation of the user interface 115 rmay be conveyed to the user interface 115 by means of a data signal in a transmission channel The user interface 15 115 may be a computational device, for example a personal computer, used by a person to play a game provided from a remote contrUer 101. Figure 3 shows an exemplary block diagram of the main components of the memory 103, The RAM 103A typically temporarily holds instructions and data related to the execution of game programs and communication functions performed by the 20 computational controller 102. The EPROM 103B may be a boot ROM device and/or may contain system and game related code. The mass storage device 1030 may be used to store game programs, the integrity of which may be verified and/or authenticated by the computational controller 102 using protected code from the EPROM 103B or elsewhere. 25 Figure 4 shows a gaming system 200 in the form of a network of devices. The gaming system 200 includes a network infrastructure 201, which for example amay be in the form of an Ethernet network. Altematvely, a wireless network and/or direct communication channels, or a different type of network may be used to lnk the gaming machines to a server, each other and/or other devices. Gaming consoles 114, shown arranged in three banks 203 of two gaming consoles 114 in Figure 4, are connected to the network infrastructure 201. The gaming consoles 114 may form paror aU of a gaming machine 100. Singe ng consoles 114 and banks 203 containing three or more gaming devices 114 may also be connected to the network infrastructure 201, which may aso 5 include bank controlers, hubs, routers, bridges to other networks and other devices (not shown). One or more displays 204 may also be connected to the network 201. The displays 204 may, for example, be associated wih a bank 203 of gaming consoles 114The displays 204 may be used to display representations associated with game play o the gaming 0 devices 114, and/or used to display other representations, for example promotional or Servers may also be connected to the network 201, For example, a game server 205 may generate game outcomes or games played on one or more of the gaming consoles 14! a database management server 206 may manage the storage of game 15 programs and associated data a a database 20$A so that they are avaiabe for dowiodig t, r ccSs iby gam-e otrKlr 101 and a Ja kot sre207 may cnrlone or m"ore ja ckpots forthe gami~ng systemr 200) Further servers |may be provided to assist in the adninistration of the gaming system 200, including for example a gaming fkor management server 20$, and a licensin 20 server 209 t monitor the use of licenses to partcular games. An administrator terminal 210 is orovded to alow an admins tortmanage te netw",o 20 and the devices connected to the network. The different servers depicted can be distinct physaic servers oogiCay distnct server processes runmng on a single physical sere The gaming system 200 may communicate wth other gaming systems other local 25 networks for example a corporate networkand/or a ide area netwo such as the InteRet through a firewal 211, The game Controlier Its programmed o provide a mbn ame a v or the return to player (TP). The RIP is the overallstatistical return to a payeof the 12 machine. For example, if a game controller 101 is operating in accordance with a RTP of 90%, a player will (statistically) be awarded with 90 cents for each $1 wagered on the machine It is often desirable to be able to alter the RTP of any given gaming machine, The RTP Srmay, for example, need to be changed to comply with various regulations (which may differ from location to location) or to comply with indviduai casino or gaming establishment requirements: The RTP of a game can be determined from the combInation of the paytabe for the game together with the specific set of symbols and the probability of winning 10 combinations o symbols occurring. The paytables may, for example, include data on the particular combinations of symbols from the symbol set which. when occurring as a gane result, constitute a winning event as well as the award associated with that winning event. The paytable or game rules may also include information asuch as the circumstances under which bonus games, free games, jackpots, and/or any other pay 15 caracteristics may be awarded, which typically also influence the RTP, ln order to allow for the RT of a gaming machine to be set to different ieveis, in one embodiment a gaming machine is provided with a plurality of different symbol sets, each with its own associated RTP, from which the game controller 101 can make random selections in order to provide a game, By making a weighted random selection between 20 symbol sets with appropriate RTP's (as discussed below) the game controller 101 can be configured tooperate in accordance with a specific RTP as required. To describe how the game controller 10 uses the plurality of symbol sets to provide a specific RP (S) an example of a gaming machine provided with two symto sets wi:l be discussed. The RITP associated with the first symbol set (i.e, the RTP if the first 25 symbol set is used during game play) is RI. The RTP associated with the second symbol set is R2. If the gaming machine was required to have a specaic RTP equal to RI, .he game controller 101 would make random symbol selections from the first symbol set for every 13 game play, Similarty; if the specific RTP of the gaming machine needed to be set at the RTP of R2: the game controler 101 would make random symbol selections from the second symbol set for each game play. A specific RTP (S) between RI and R2 may be provided by the game controer 101 5 making a weighted random selectionbetween the first and second symbol sets. The selected symbol set is hen used n a game pay of the game t is noted again here that the RTP is a statistiUcal RTP across a distribution of games raher ta a sigegame. S =the specific RTP required for the gaming mach ine 10 R1 = the RIP of the game if the first symbol set is used R2 the RT? of the game if the second symbolsetis used Provided RI 65 R2, there extets a probability p such that: 0 in $1 pR (I p)R2S 15 Accordlegy, p mray be calculated according to the following: (R2 - R1) in order to achieve the desired RTP value this rmuia may be implemented in a variety 20 of ways. For example, the game controller 101 may use the value of p and for any given game select either the first symbol set or the second synbo setrom which the random symo sections are made during game p, in weig random slectn process such that the probabity of selectingfrom the first symblsinte seectn press p. and the probability of selecting from the second symbol set is (1 p The value of p or a mathematicaly equivalent or similar value may be a parameter of the gaming machine able to be set to a different level using an appropriate interface to the gaming machine, with appropriate safeguards to prevent unauthorized modification. Alternatively, the ye ue of p may be set during game design and 'hardcoded into the 5 gaming machine, In the latter case a range of different gaming machine controllers may be manufactured whereas if the value of p is settable, then a generic machine may be produced, which is subsequently set up for a particular jurisdiction or venue by setting a value for p General example i 10 By way of example, the RTP associated with the first symbol set may be 80% (i~e. R1 = 80%) and the RTP of the second symbol set may be 100% e. R2 =100%) If the gaming machine was required to have a specific RIP of 90%(i a. S =9%) then, using the aforementioned calculations, p 0, That is, when selecting whether the first of second symbol set should be used during a given play of the game the game 15 controller 101 undertakes a weighted random selection roc which has a 50% chance of returning the first symbol set for game play and a 50% chance of retuming the second symbol set fo game play. Afternaively if a specificRTP of 95% required (iT. C 95% o 5 a nd tgame controller 101 selects a symbol set via a weighted random selection process which has 20 a 25% chance of retuming the first symbol set for game play and a 75% chance (e 1 p) of retuming the second symbol set for game play. General example 2 By way of a second example, the RIP associated with he first symbol set may be 60% (R1 = 0%) and the RTP associated with the second symbol set may be 1000% (R2= 25 1000%). Kf the gaming machine requires a specfi RTP of S0%~ (S =90%), then p =91/94. in the weigh ted selection process, therefore, the chance of returning the first symbol set for 15 game play would be 91/94*100 (approximately 97%) and the chance of returning the second symbol set for game play would be (1-(91/94))*100 (approximately 3%). As will be appreciated, the RTP of the gaming mache can be set at any value that falls between (or is equal to) the RIP associated with the first symbol set end the RTP 5 associated with the second symbol set. Figure 5 provides a depiction of the above process as used in a sample game screen 500 for display on one of the gaming display 106. The game screen 500 includes a symbol display area 502 which provides a plurality of symbol display positions 504. The game screen also includes a display for a credit meter 516 a meter indicating the wager 10 placed by a player 518 and a display for a win meter 520 showing the amount, if any, won by a player. During game play the game controller 101 determined which of the symbol sets 522 or 524 s to be used for game play, and then populates the symbol display positions 504 with a random selection of symbols from the selected symbol set, 15 Where more than two sets of symbols are provided, the lowest RTP value achievable for the gaming machine will be the lowest RTP associated with a set of symbols, and the highest RTP achievabe for the gaming machine will be the highest RTP associated with a set of symbols. in order to provide a specific RTIP fallng between the lowest and highest RIP the game controller 101 is configured to make a weighted random 20 selection of which symbol set to use for any given game play in a manner similar to that described above. The selection may be made from all of the available sets of symbols, or the game controller 101 may select from combinations of two or more symbol sets, but less than all available symbol sets, to achieve the specifically required RTP. in the later case the symbol sets that can not be selected are never used for the particular 25 'plementation of the gaming machine, but may be used for other implementation. For example. if three alternative symbol sets A, 8, ,and C are provided having associated RTP's of RI, R2 and R3, a specific RP may be obtained by a combination 16 of RI and R2, a combination of R2 and R3, a combination of R1 and R3, or a combination of R1, R2 and R3, Spinning reel game example By way of further example, he present invention may be used in relaton to a spinning 5 reel type game. in this type of game the symbol sets are provided in the torm of a plurality of reel strips, each reel strip including a number of adjacent symbols. During game play each reel strip in the symbol set is "spun" by the game controller 101 and randomly stopped to display a subset of symbols on the display. Prizes are then awarded in accordance with a payable. 10 In order to alow for the specific RTP required for the gaming machine t be changed, the garmng , achine may be provided with two or more entire different sets of reel strips (i.e. two or more different symbol sets) each set of reel strips resulting in a different RTP. As described above, when playing the game the game controller 101 can make a weighted random selection of which set of reel strips to play for any given 15 game, and the weighting used in that weighed random selection will determine the statistical RTP for the gaming machine, As an alternative to providing entirely different and distinct symbol sets, however, a specific RTP could be provided by providing different reel strips. For example, the game machine may be a reel type game in which 5 reels are "spun. Referring to figure 5, the 20 display area 502 may be conceptually broken into a number of reel strip display positions corresponding to columns 506 to 514. During game play the game controller 101 "spins a reel in each reel strip dilsplay position 506 to 514, stopping the reels to populate the symbol display positions 504 with symbols. in such a game it would be possible to have 4 of the reel strips associated with four reel 25 strip display positions (e.g, 508 to 514) constant (Le. not changed between game plays) and provide the required specific RTP for the gaming machine by a weighted random selection of a reel strip to use in only one of the reel strip positions 506. By way of 17 example, in figure 6 two reel stripsare shown for seiectioreel strip 602 and reel strip 604. For example, reel strip 602 could provide a gang machine with a particular RTP (R1) when used in combination with the 4 reel strips populating reel strip display positions $ 508 to 514, and reel strip 504 could provide a gaming machine with a different RTP (R2) when used in combination with the same 4 reel strips, in this scenario, a specific required RTP for thle game machine that falls between the RTP associated with reel strip A 602 and the RTP associated with reel strip B 604 can be provided via a weighted random selection of which reel strips 602 or 604 to use in a given gane play. 10 The weighting of this random selection may be calculated according to the formula described above, with reel strip A in this example the first symbol set, and reel strip B the second symbol set. In one embodiment the determination of which reel strip to use is determined or each and every game play of the game. In another embodimet, the determination of which reel strip to use may be determined for a group of game plays, 15 for example the next ten game plays. in the latter case, the two reels strips 602 and 604 may be provided to appear the same so that the player can not determine which reel strip is being used, in the earlier case, the reel strips may be visual different, it would, of course, also be possible to change any number of reel strips (e. any number of symbol sets) in this particular example (e.g, holding three reel strips constant 20 and changing the remaining two reel strips) provided the RTP associated with each combination of reel strips is known (which, In turn, allows the correct weighting to be used in the weighted random selection process), For example, in one embodiment there may be two options for the symbol sets, one with a combination of a first two reels (which may be the same or different to each other) in reet strip display positions 506 25 and 508 and another with a combination of a second two reels in those positions. in another example there may be two different reels available for selection in the reel strip display position 506 and two different reels avai bte for selection in reel strip display position 508 and the reel used for each display position 506, 60$ may be determined independ enuy of each other. This leads to four different possibilities for the 18 symbol sets and the RTP can be determined for each and the probability of selecting each set to obtain a required specific RTP for the entire game. in addition, there may be three or more different options for symbols for a reel strip display position, Some efficiency however may be obtained if only two symbol sets are provided, In 5 addition, some efficiency and/or consistency between implementations may be obtained if only a part of the symbols sets are changed, for example one reel in a set of 3 reels or one deck of cards in a game that uses five or six decks of cards. The game may be designed so that the visual difference between the two alternative games that result from this process is ail. For example, the reels may be shortened 10 in comparison to the usual 20 to 25 symbols so as to magnify the effect of swapping one symbol on one reel with another symbol on the alternative reel to that reel. For example a WilD symbol (W) may be changed with a SCATTER symbol (C). The reel strip may for example be between 7 and 15 symbols long. The -temative reels may have the same length or may have different lengths. 15 Combined reel strps As a further variation to the above reel type game example, instead of performing a weighted selection process to determine whether reei strip A or reel strip B should be used in any given game in order to provide a specific RTP, a single reel strip comprised of instances of reel strips A and B could be created and used for every game play, 20 The ratio that reel strips A and B need to be combined together in so as to provide the specific RTP required by the gaming machine is given by the formula for calculating p as described above; (R2 - RI) 25 where: t = the specific RTP value required for the gaming machine 19 R the RTP provided by the gaming machine ifreel strip A is used R2 - the RTP proMded by the gaming machineif reel strip B is used If p is expressed as a traction in the forrn x/y (in its simplest form), the RP value required for the gaming machine can by provided by always using a reel strip that is a 5 combination of x instances of reel strip A linked to (y .x) instances of reel strip B. By way of example, figure 7 provides a representation of reel strip 602 and representation of reel strip 604 (of course in practise it is likev that both reel strips A and B would be comprised of larger numbers of symbols) The end symbols of each reel strip are "jone to another reel sip p create a loop. 10 if the gaming machine requires a specific RTP of 90% (S 90%) and the RIP associated with reel strip 602 is 80% (W a R1 =0%) and the RTP associated with reel strip 604 is 100% (i.e. R2 = 10%) the above calculations show That p = % fi) in this case, therefore, rather than making a weighted random selection process between reel strip 602 and reel strip 604 to determine which re strip should be used for a piay of the 1 qame (the weighted random selection process having a 50% probability of returning reel strip A and 50% probably of returning reel strip B) a single reel 614 that is a combination of one instance of reel strip A 602 and one instance of reel strip f 604 can be created and used for each game play As can be seen, in the combined reel strip $14 the ast symbol 608 of re strip A 602 is adjacent the first symbol 610 of re strip B 20 604 Alternatively, if the gaming machine requires a specific RTP of 95% (S = 95%) the above calculations show that p = % (025) Therefore, a specific RIP of 95% can be provided by playing the game with a combined reel strip 61$ that is comprised of I instance of reel strip A 602 and 3 instances of reel strip B 604. 25 As will be appreciated, randomly spinning a combined reed strip as created above during game play is substantially equivalent to swapping between reel strips A and B in the ratios required to achieve the specific RIP required for the gaming machine As will also be appreciated where virtual " reel strips are to be used by the game controller only 20 a single copy of each reel strip need actualy be stored, w the combined reel strips generated as required. To obtain a higher granularity in he possible specific RTI values, a higher number of reel strips may be used, In one embodiment the game is determined as if all reel strips 5 of the same type are joined together in a group. For example when the reel spins, it may spin through 10 instances of reel 602 and then 0 instances of reel strip (04 before returning to the 10 reels 602, When combing multiple reel strips into a single reel strip care should be taken to ensure that any transitional sections of the combined reel stnp (ie. a section of the reel 10 strip where a particular instance of a reel strip finishes and an instance of a new reel strip, or a new instance of the sane reel strip, begins) do not significantly alter the RTP of the gaming machine from the specific RTP required, it is noted that the reel srps depicted in figure 7 are for general ilustrative purposes only, and the specific combination of symbols depicted on these reel strips may not be appropriate depending 15 on gaming marine requirements of specific jurisdictions. Other variables As a further embodiment of the invention it would be possible to provide a gaming machine with a single set of symbols and with two or more paytables relating to those symbols. in the same manner as described above, if one of the paytabIes when used 20 with the set of symbols provides a RTP R1, and a second paytable when used with the set of symbol s provides a RTP R2, then the gaming machine may be configured to provide a specific RT S, where RI < S < R2 by making a weighted random selection of which patabie should be used for any given game. Still other variables may be used to achieve different return to players, allowing 25 weighted selection between the resulting plurality of games that are possible. For example the RTP of a retriggerasle game where the base and feature have the same RTP may be defined as: 21 Where B is the return provided by a base game of the game, t is the probability of a feaure game occurring, n is a number of free games provided in the feature game and m is the multiplier of the prizes that applies for the feature game, 5 For this game, any of the variables B, m, a, or i may be varied to obtain a required RTP, B may be varied by changing the symbol sets as described herein above, m or n may be randomly selected between two values (or more) according to a weighted random selection process to result in the required RTP, if t is a symbol combination then this may be varied by changing the symbol sets. If the trigger event for the feature game is 10 determined independently of the symbols then that determination may be switched between two deternination methods with different probabilities For example in one game the trigger event for the feature game may be the selection of the number 1 in te range I to 100 and in another game may be the section of any of I to 20 in the range I to I1 15 As wil be appreciated from the preceding discussion the characteristic that is varied may be solely within the base game or solely within a feature game, it would also be possible to vary more than one characteristic, with the consequent increased complexity in determining the overall RTP and appropriate weighting in the selection process, Figure 8 shows a process flow diagram of processes performed in accordance with an 20 embodiment of the present invention In step 1, the RTP for the gaming machine is set. This may be set, for example, in accordance with the geographical location in which the game is to be used and the regulatory requirements of that location. If a suitable game controller 101 is used, the RTP of a gaming machine may be changed at any Ume either by direct interaction with 25 the gaming machine through the user interface or via instructions sent to the gaming machine over a network connection. As wil be appreciated, however, suffcen security should be implemented to prevent unauthorised tampering of the RIP Altematively a 22 game may be manufactured wth te RIP pomanenly set as described hr ad shipped with that fxed RTR In step 2 the weighing required to be used for the weighted random selection proves in order to provide the gaming machine with the required RTPicalculated and stored Sonthe gaming machine. The weighting i calculated according to the formulae discussed above. The weighting may be calcu ated by the gaming machine itself and stored as a variable or may be calculated by a manufacturer of the gaming machine and stOred as a onstan steps and 2 relate to the manacture and/or setting up of a gaming machine, Steps 3 10 to 7 apply to play of he gaming machine In stlep 3 the gmconrer11ontsthbllacceptor and/or coin ipt110 and/or information received b the card/ticket reader 108 or network card 112 for a depose of credit and in esponse causes the hardware meters 104 tincrement according to the dCoi nt of tegme The gen e 15 07 tor the sput of a eager In step 4, and provided a use as sufficient reds ne user tiateWa,,' Sarne, In step 5 the game controller 10 determines the symbol set that wil be used for the game according to the weighted selection process descnbed herein assuming the embodiment where there are a plurality of altenative symtol sets) 20 In step 6 the game controller 101 makes a andom selection of symbols from the symbol set selected in step and displays the results awards the award to the player. W e appreciated, fhe symbol sets seledin he weighted o are 25 symbol sets used in the base game, he determination of which symbol set use for any giver game play made in step 5 may be made atany tine prior to making the sybo sletin f tc . ite ltrntiesybos et o ohe arabe ha afet 23 RTP is for a feature game, then the process may be modified so that step 5 is completed only when required ie. only when a feature game is played. While the foregoing description has been provided by way of example of the preferred embodiments of the present invention as presently contemplated, which utiise gaming 5 machines of the type found in casinos, those skilled in the relevant arts will appreciate that the present invention also may have application to internet gaming and/or have appIication to gaming over a telecommunications network, where handsets are used to dlay game outcomes and receive player inputs. Where in the foregoing description reference has been made to integers having known I0 equivalents, th equivaleequivalents are hereby incorporated herein as if individually set forth. Those skilled in the relevant arts will appreciate that modifications and addons ns to the embodiments of the present invention may be made without departing frm the scope of the present invention. 15 t will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings, Ail of these different combinaIons constitute varo us alternative aspect enion 20