There are a lot of different ways to think about optical illusions. But, whether you consider them a flaw in human sight or perhaps a once useful evolutionary trait, we think they're downright fascinating. Take this GIF from National Geographic's Braingames. The three yellow dots on the rotating orange square are going to completely disappear right before your eyes and then reappear in a flash.
Here's how it works:
Look at the GIF below. Focus intently on the red dot in the middle and try not to move your eyes around too much. The yellow dots on the periphery should fade away and when you begin to shift your sight elsewhere, they have inexplicably returned to the moving orange square.
That's called motion-induced blindness (MIB), one type of visual disappearance. Here are some other great GIFS, although don't worry, these just look cool — they aren't going to tease your brain quite as much.