I got Jack doing some signing on my camera today...in the past two weeks, he has really started applying what we have been doing with him since he was a newborn! As of now, Jack knows these signs: more (his first sign), I want, eat, all done, mama, ball, milk, and all of the gestures to Itsy Bitsy Spider (and he is waving and clapping). I feel like things are clicking for him all of the sudden...the expressive is catching up to the receptive...so here he is!
Edited to add: He just added please and happy to his signs. :-)