Fascinating topic. But as far as I know the patterns in cats are not related to skin. I think they are related to genes. After all what we see as patterns are individual hairs of different colors. Some animals like zebras have the same stripes through generations. This is not very interesting. In cats I'm sure there is a random process in effect. But this random process is also "aware" of the symmetry of the body, like having the same black patch on each ear. Or having a black tail in otherwise white cat.