Jumping Jack

Generally, a mirror reflects a normal-sized, accurate to side and erect image of people or objects in front of it. But if you position yourself in front of the mirror as described  above you'll only see a reflection of one half of the body. In a second mirror, placed in a right angle with the first one,  you can supposedly see your whole figure. In reality, it is a made up image of the one half of the body. Since you are used to a body consisting of two arms and two legs nothing seems out of the ordinary. But if you lift the leg and arm in front of the mirror it looks like you are floating. Move your leg and arm up and down simultaneously  and it looks like you are doing jumping jacks.