Favorite activity

I think we have mentioned before that Alder loves his collection of 20 or so matchbox cars. He will rise from a nap or arrive home from being gone and state "I play my cars". He then goes and gets the Tupperware container that houses them in his room and brings them to wherever he decides is best - typically wherever we are at the moment. He then proceeds to take them out one by one and line them up. You would think this would take 1 minute or less, but the concentration he puts into this activity is much more than that. He makes sure to place each one in the proper direction and the container of cars is typically several steps away meaning that he must walk over to it to fetch each car. I am thinking this is a very normal 2-year-old behavior, but we can't help but wonder if this is somewhat indicative of OCD ;). Not surprising I guess considering that Jason and I are both pretty particular.