thanks - i just figured out what that sliver is.
take the initial image i posted with "here's one of the common 7", and then take the one with a sliver. flip back and forth between them.
Ah, that makes sense. Oddly enough, those two images are the ones I couldn't find elsewhere. Do you remember where you found them? I found the one you were looking for here: archive.is/XaXCH