As it turns out, William can actually pedal his tricycle by himself. We've been encouraging him to do it for awhile, but usually he'll pedal a few times and then whine for us to push him again. See below:
But after getting a report from Miss Aubrey that William is a fast-and-furious pedaler at school, we've decided to encourage him to power his own self a little more often.
But of course, sometimes he still wants Daddy to push him.