Just saw this cool thing on Tumblr, basically it's a .gif recreation of a phenomenon known as Benham's Top (or Benham's Disc). It's a pattern that, when spun, generates arcs of color on the disc. However, the cool thing is that there's a massive variation on who sees what color, so it's likely that two different people will not see the same colors. The .gif is a bit seizure inducing, so I'm putting it in the spoiler tag. I see alternating arcs of black and gold. What colors do you see?