"I made a joke"

We were driving home today from a gathering with friends...it had been a long day of different things going on. We were stopped at a red light near a farm equipment store that we see all of the time. Connor saw an edger in the window...it took the shape of a motorcycle...at least in the eyes of a 3.5 year old. Once we figured out what he was talking about, we let him know that it wasn't a motorcycle. We told him it was an edger. Of course, his next comment/question was: What's an edger? I told him that it is a machine that goes along the edges of the grass to make it look nice. He then said something like..."and that's why it doesn't have a tail." He then said, "Ha, ha, I made a joke. Get it? ha, ha. I made a joke!" My husband and I looked at each other. We had no idea what he meant, but we laughed. He felt so good...he made a joke!