Cool Tree Art On Avenue Y – Anyone Know The Story?

I spotted this sign hanging from a tree on Avenue Y and East 13th Street the other day. It was a pity I didn’t have a better camera on me.

Hopefully more stuff like this pops up around the neighborhood. It was a welcome sight to shake me from my post-accountant shell-shock. (Speaking of things to nail to a tree…)

Anyone know the story here?