Here's the rest of the stuff from that sketchbook.
Most of these are a little hard to see, given that they were lightly drawn in photo blue pencil. The first one is Leonardo wielding the "Sword of Tengu".
Here's a Turtle with a three-sectioned staff...
... and Leonardo with a kusari-gama.
I'm not sure why I did this one, other than the fact that it was fun. I like this wacky one-wheeled vehicle -- looks like something Donatello might cook up in his spare time.
Last up is the drawing I did as the basis for Mike Dooney's painted cover to TMNT #28. -- PL