This is the image on my computer desktop at work, and has been since we went to the City Museum in St. Louis several months ago. Until today I never noticed that Boy was doing something weird with his hand. At first glance I thought he was making the sign of the devil which I had been painstakingly been teaching my daughter (she does it now, while screaming Rock 'n Roll and sticking out her tongue).
On closer inspection I came to my senses and realized which of my kids I was talking about.
Live long and prosper!