Natural optical illusions fascinate us because they test our ability to perceive our surroundings. It also provides important insights into how the human brain works. Researchers have been studying how optical illusions affect the human brain for years,

and they have devised a number of experiments that demonstrate how different parts of the brain respond to optical illusions. Now is the time to put your observation skills to the test. Use this Odd Shell optical illusion test to find a hidden Odd Shell in 7 seconds or less.