In Shake Shake Tower – this game's original name – players start the game with eight 3D curved polyomino pieces in a single color, then take turns placing them on a swiveling, seesaw-style platform. Gravity pulls the platform and pieces from side to side as the tower rises, so players might have a tough time adding a piece to the stack – especially since each level must be filled before players can play on top of other bricks. If a player can't legally play, she must skip her turn, so play strategically to block others while leaving yourself room to grow!
If you knock pieces off the tower, you keep them on the side, losing one point for each brick in such a piece. When a player plays her final piece, the game ends. Players then score one point for each brick of theirs visible from a top-down view of the tower. Whoever has the high score wins.
Tremblex, a revised version of Shake Shake Tower, uses the same pieces and nearly the same scoring method, but players are free to place pieces as they wish on the tower – with one small exception that drives play in a different direction. Each piece you place must touch one of your pieces already in play; if all of your pieces have been covered by other players, then you're forced to sit out until someone else knocks pieces off the tower! Once this happens, all players are back in the game. The game ends when a player places her final piece, and players tally their scores, earning one point for each brick showing from a top-down view of the tower, losing one point for each brick in pieces knocked off the tower, and collecting a three point bonus if their piece is highest up in the tower.
Tremblex includes variant rules as well, such as a cooperative mode in which players try to complete the tower with no holes and a two-player game in which opponents place pieces only on their half of the platform, trying to scale higher than the other player in order to win.