A question about sprites in Hype
Look at the SAT in this picture
 http://picasaweb.google.it/lh/photo/8ztuH0XWlozv6Luymw9yXA?feat=directlink
I noted that in the SAT each object appears twice, once with its color, once in black with a lower plane but at the SAME position.
All black versions are in lower planes wrt the colored planes.
All planes mirror at each frame (but colored sprites stay always before than black sprites).

Does anyone have studied why Hype uses teh black sprites (that shoudl be in theory invisible as covered by colored counterparts)?
Does anyone have a clear idea on how sprite multiplexing works in this game?