Warm your eyes up a little by changing focus then look at the following image :
Squint your eyes till both soda cans are superposed then tweak your eyes' focal distance until both cans are properly clear. They are then see in 3D
A few others for fun :


Squint your eyes till both soda cans are superposed then tweak your eyes' focal distance until both cans are properly clear. They are then see in 3D

A few others for fun :

