7.

In most cultures a corpse is laid on its back, and gravity pulls the fluids down, giving the upper sections their waxy pallor. The lower sections darken as the blood settles, except in those places where the body is touching the surface on which it is laid. There, the pressure of the weight of the corpse pushes the blood from the tissue, forming areas that are much lighter than the rest. One of those areas is across the shoulder blades and upper back, and it takes the form of perfectly symmetrical wings. The Cathars believed that humans are fallen angels, trapped in a material body because of the sin of the rebellion.