The design consists of the shape, configuration, pattern and ornamentation of the design show in solid lines in the drawings. FIGURE 1 is a first perspective view of a first variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 2 is a second perspective view of the first variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 3 is a third perspective view of the first variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 4 is a top view of the first variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 5 is a bottom view of the first variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 6 is a front view of the first variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 7 is a back view of the first variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 8 is a first side view of the first variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 9 is a second side view of the first variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 10 is a first perspective view of a second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 11 is a second perspective view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 12 is a third perspective view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 13 is a fourth perspective view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 14 is a fifth perspective view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 15 is a top view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 16 is a bottom view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 17 is a front view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 18 is a back view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 19 is a first side view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 20 is a second side view of the second variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 21 is a first perspective view of a third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 22 is a second perspective view of the third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 23 is a third perspective view of the third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 24 is a fourth perspective view of the third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 25 is a fifth perspective of the third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 26 is a top view of the third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 27 is a bottom view of the third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 28 is a front view of the third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 29 is a back view of the third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 30 is a first side view of the third variant of the CONSTRUCTION BLOCK in accordance with the design; FIGURE 31 is a second side view of the third variant of the CONSTRUCTION BLOCK in accordance with the design; The broken lines form no part of the design.