Julian Cash is well known, among other things, for being the photographer of the open source communities, as you can see from his photo stream, or this picture of his newest book.
For more books, you can look at The human creativity project.
At OSCON 2008, participants could attach one or more ribbons to their badge, to state their affiliation with a project or an idea. When the sought ribbon was not available, there were blank ones that users could fill with their favorite topics.
As you can see here, I made free use of the ribbons. Julian Cash, instead, stated his affiliation with Perl quite strongly.
Thanks for sharing your art, Julian!