the leopard popped up in peter kahls piebald projects. all it is is a visual het.. or if you want, call it a co-dom with the super form being piebald. same thing. basically he noticed from some of his piebalds offspring that the hets weren't normal looking. check out the leopard orange dream. the pattern looks very similar to a piebald minus the white. "visual hets" and co-doms are pretty much the same thing. ex: het red axanthics, russo (het BEL), and i'm sure you've seen people call lessers and butters "het BEL"