I've started before the jam's beginning. I was reading the documentation and the tutorial, and then I had an idea and preferred starting right away instead of waiting.
I said in the "introduce yourself" topic that I had almost finished the coding, but finally I needed to add a puzzle and I still have no idea for it, so the pace slowed down. (Also, I haven't done anything in the past couple days, for diverse reasons.)
Trying to force myself now. After all, they'll be the graphics to make, too.