This is made possible through something called a lenticular lens – a corrugated sheet in which each ridge is made up of a convex – or outward-curving – lens.

这是通过一种叫做柱状透镜的东西实现的，柱状透镜是一种波纹状的薄板，其每个凸起处都由凸透镜（即向外弯曲的透镜）组成。