The Buffalo group at the American Museum of Natural History is not my favourite J.P. Wilson Diorama but there is a treat if you look inside the return on the far right hand side (top image) where a buffalo painted on the background crosses between the far right hand edge of the background and the painted section of the return to the viewing window. The part of the animal on the background is painted normally but on the return it is painted anamorphically. Pictures from inside the diorama reveal a pot bellied buffalo, at least on its left hand side, to compensate for the viewing angle. The furthest away part of the buffalo is painted on the surface closest to the observer.
By the way, note that the horizon is not adjusted anamorphically on the return – perhaps because the viewing window is so wide that it is hard to know where to imagine the observer’s eye?.