O’Reilly distributed at this years StrataConf some very nice buttons: as I wanted to use them I made some photos of them and want to share them you in a Google+ Photoset.
You can use the photos for free, citing me as the producer. (CC BY-NA)
The photos are big & detailliert enough to use them as wallpapers & slide backgrounds in case you like them.
My favorites are:
Have fun using the pics!
Daniel Koller 