My son Matthew is a second grader who loves school, reading, Lego's, Star Wars and just about everything else except cheese. My wife and I, both art teachers, have never pushed him, or his sister Clare, toward the arts. We do the occasional art project together but we refrain from harsh criticism of their skills. We definitely don't push it!
During music class they were given some Popsicle sticks to work out some music theories (which I don't understand well enough to explain here...second grade stuff). When finished, they had a few minutes to just create something with the sticks. Not sure where Matt picked up the 3-dimensional thinking, but he must be watching his parents work or just thinking through it on his own. I guess it is good to do ones work in front of them even if you would bet your right arm that they weren't paying any attention at all.