Base on @jgm’s design on pandoc logo - Google Groups, see below.

Just a concept though. I simplified the idea since I can’t think of a nice way to have 2 documents there (it will becomes too rectangular). If we really want to put the documents there, they may be added at the tip of the arrows?

I also tried drawing it not in straight lines but curves. I wanted to make it looks like a smily face, but so far my attempt has been a creepy face…