Optical illusions harness the shift between what your eyes see and what your brain perceives. They reveal the way your visual system edits images before you're even made aware of them like a personal assistant, deciding what is and isn't worthy of your attention.
People were creating optical illusions long before we knew what made them work. Today, advances in neuroscience have pinpointed the visual processes that fool your brain into falling for many of them. Others still elude explanation.
Here, a selection of eye- and brain-boggling illusions, and explanations of how they work.