Most dance pads are divided into a 3 by 3 matrix of square panels for the player to stand on, with some or all of the panels corresponding to directions or actions within the game.
3
GameServer单例用于它的位置数组,其中保存了游戏面板上每个格子的当前状态。
The GameServer singleton is used for its positions array, which has the current state of each square on the game board.