Pay attention to the details

I should have done that before I posted pictures in the last entry. Apparently I was oblivious (for several days) to the fact that Joel colored on the bottom footboard with a black marker. I noticed it today, but was informed that Dad had already seen it. I thought the drawing looked like lungs, but apparently Dad saw something else (at least according to Joel). So, what do you see? (Scroll down for Joel's answer of what it is.)













Joel says it's a motorcycle. Do you think there's a budding artist in my house?