Ask the spectator to put the board in each of the envelopes, then tie it vertically with the rubber band, performer is not allow to watch it while spectator is doing it.
请观众随意将不同颜色的板子，分别放入不同颜色的信封里，然后用橡皮筋垂直的固定住信封，此过程是在表演者完全看不到的情况下进行的。
youdao
应用推荐
模块上移
模块下移
不移动