As humans, we rely on our sense of sight the most of any of our senses. We use it to navigate our surroundings and protect ourselves. Even with the frequency and reliance we place on this sense, it is far from perfect.
Optical illusions either trick our brains perception of the images our eyes report back or or our eyes are unable to make a clear distinction of the images seen. The tests below are a mix of both, each one has a time limit, and the answers on the flip side.