Interesting that the couch's covering isn't recognizable as the slain bull, though I'm not sure I would blame the artist's lack of skill for the omission. Someone had to be directing the artist, as it's REALLY unlikely that every piece of Mithraic art had a single point of origin that every subsequent artist drew upon. Instead, let's think of the decorative stripes as an elaborate dorsuale.
;-)
I am glad the snake got an invitation to the feast.