Today’s collection of mind-bending optical illusions and confusing-perspective photos is here to give your brain a workout.

Photos: (1) MRI of Ed Viestur's brain; (2) Howard Donner and Gail Rosenbaum test David Carter (center) at sea level; (3) Howard Carter uses stopwatch to time David Carter; (4) David Carter reads ...

The optical illusion shows a room with a lot of stuff lying around. Only someone with very high observational skills can spot ...

Such kind of brain teasers doesn't require mathematics skills but are a simple test of knowledge and lateral thinking. However, it sure feels great when you figure out the answer in a few moments.