In the realm of optical illusions, identifying a unique number ... allow your vision to become one with the swirling patterns ...

Optical illusions play tricks on your brain and can make you see things that aren't really there, from static images swirling around the page to images that stay with you even after you look away.

An curved arrow pointing right. These vortex spheres create beautiful optical illusions that resemble swirling galaxies. They are handcrafted by New York artist Scott Pernicka at Internal Fire Glass.