Shakewave - The Ultimate Stacking Blocks Game Challenge! Stack Rollers To Form A Tower As High As Possible On A Rotating Base Without Causing It To Collapse! The rollers refuse to stay where you put them! Instead of the traditional stacking blocks, the players place the "rollers" onto the "rotatable game base" Spin the spinner to place the roller(s) (1 or 2) or turn the base Keep the tower stable and balanced Promotes hand-eye coordination, fine motor skill and depth perception training. Specifications Weight: 1.5 lbs