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.
Chu demonstrated the " invisibility" at the event, and he made his legs disappear directly with the help of a magical material called " lenticular grating" that allows light to be refracted regularly.
When multiple of these lenticular sheets with different lens distributions are layered in just the right way, they are able to refract light at a myriad different angles to create " dead spots " .
Sometimes, this kind of turbulence is actually visible thanks to rotor clouds in the eddies and lenticular clouds over the tops of the mountains, but ideally, you know about it before you see it.