Thanks again for all your responses! It certainly makes me feel like I'm onto something. DS is not a kid who likes to color, draw etc. and I think his little hands fatigue quickly. Also, I learned that the children do their writing centers right before "specials" (art, computers, music) and I feel that DS just wants to be done and as children start to line up, he rushes through the work. At home, it improves slightly when he takes his time, but it's still very faint just not as shaky.
NanRos- funny you mention mazes. The only thing that DS draws voluntarily are treasure maps and mazes. Those are one of his earlier drawings and he is still fascinated by them.
