When I was a teenager I used to listen to "The Dr. Demento Show" on the radio. They had a song about "Star Trek", and the lyrics said:
"Star Trekkin' across the universe, only going forward cuz we can't find reverse!"
Kevin has the opposite problem. He has mastered using his feet to push himself backwards in his little walker until he runs into a wall or furniture. He gets so frustrated and mad that he can't keep going, but he doesn't know how to go forward. Could be worse, I guess. Picture this kid at 16 with a driver's license!