Can't remember the name of a music app

Hi guys!

I have a kind of a silly question. I can't remember the name of an app that was demo-ed on an Apple Event, I was hoping you guys could help me locate it!

It was presented by its developer on stage, in the beginning of the app store period, and it's a music app that combines more than one instrument..
I remember that, in the end, there's a bunch of little brown squares that play blues' sequences.. and the resulting song was pretty cool!

Sorry if the info's a little poor, but that's all I can remember. Oh, and it was surely before 2010. Not sure if it was mwsf, wwdc, or a september music event..

Thanks a lot!

-Alessandro

 

YES! That's the one!
thanks a lot