It is the CMU thistle. I put together the image a while ago, so I'm a bit hazy on the details, but from what I remember I found the biggest PNG file of the logo that I could and used the Photoshop wand tool to remove the background. Any fuzziness on the edges will have gone away from being shrunk down to fit on my normal avatar.

They did use the tilted square when I first started there, but some time around my junior year they decided to just go with the font they use nowadays.

Hello,
I am Pogo and I wanted to ask after your avatar. It seems to be a takeoff on the Carnegie Mellon thistle logo (as opposed to the tilted square.) How did you yank the golden thistle part to overlay on the JJ without grabbing any of the original thistle background?

Pogo