Choo Choo? Shoe Shoe.

I was here in the family room, on-line Christmas shopping my little heart out while Simon was downstairs in the foyer happily playing by himself.  I kept hearing him say "choo choo", so I assumed he had made up some kind of train game.  Awesome.  As long as I could hear him playing, I felt less guilt about being on the computer while we were home alone together.

"Hey Mom!  Come look what I made!"  Uh oh.

He was so proud of his OCD organizational skills.  Please tell me this behavior is a normal developmental stage for 2 year olds...