这个戏法使用的是橡皮筋，它的名称叫做“魔法之手”。它是刘谦的代表性幻术之一。它在很多魔术道具商店中被展出。

This trick USES elastic bands and is called "magic hands". It is one of lu Chen's trademark illusions. It's on display in many magic prop stores.

youdao

试一下这个小戏法：把一块橡皮或者相似的东西举起一臂长，在月亮接近地平线和后来升得更高看起来小一些的时候来测量它。

Try this trick, though: Using a pencil eraser or similar object held at arm's length, gauge the size of the moon when it's near the horizon and again later when it's higher up and seems smaller.

youdao