TOWER STACK™ BISON: Standing proud with a new stack series with 16 vertical reel positions and up to 150 lines. Players can select to play up to 3 frames totaling 150 paylines. Playing the PLUS FACTOR ante bet adds an extra selectable play area according to reel angle and turns all symbols on reel 5 wild. In the 8 free games, special reels with a greater number of the “Top” symbol are used.