“The Da Vinci Code” addresses several issues surrounding “The Last Supper” (the event, not the painting). Most, if not all of those issues, and their explanations, are silly.
But I have one deep question about “The Last Supper” (the painting, not the event)…
Why are all these people sitting on the same side of the table???
charley's blog 
Probably for the same reason they do it on TV shows – you’ve got to leave one side open for the cameras to get a clear shot.
That makes sense. Da Vinci WAS ahead of his time.
It’s Leonardo
I agree with Blackmore. It’s the “All in the Family” type setup.
On the other hand, just think of all the trouble deciding who would be facing the artist, and who not.