Tractate Negaim - Chapter 4 - Mishnah 10 נגעים פרק ד׳ משנה י׳

A bright spot the size of a split bean spread to the extent of a split bean, and in the spreading there appeared quick flesh or white hair, while the original spot disappeared: Rabbi Akiva says: it is unclean. But the sages say: it must be inspected as a new one. A bright spot the size of half a split bean with nothing in it, and then there appeared a bright spot the size of half a split bean and with one hair, this is to be isolated. A bright spot the size of half a split bean with one hair and then there appeared another spot of the size of a half a split bean with one hair, this is to be isolated. A bright spot the size of half a split bean with two hairs and another spot of the size of half a split bean appeared with one hair, this is to be isolated.