Whenever Dao plays with his model trains, he has to have five cars as a set. I didn’t really get it until the other day when he asked me to set up my train to play with him. I just put together a bunch of trains, but he said, “No daddy, you have to the main engine first [Thomas, Percy, James etc.], then tender second, then freight car, then two cabooses.” My son is now officially a connoisseur of train. Here is their early Christmas present.