A few months ago, (likely as a result of seeing her parents nearly constantly pecking away at their laptops) our daughter started to pretend to be on the computer herself. She created this here computer. So, some thoughts (Besides the "awwwww", which I do say when I see it) :
1. We already know that kids develop competencies with real life skills through play that imitates what they see adults doing all day. So, score one more for developmental psychology and the value of play. I would be interested to find out if there is recent research on how computing shows up in pretend play. I know, lmgtfy.
2. It's interesting to imagine what letters look like to four year olds. They have a clear pattern - a letterness - but they are not quite known yet. I guess it's how Greek looks to me - "I kinda know that letter is a whatsit called, looks like A but does it say L or something? And that one, whoa what does that one do, I don't know..."
3. It's a nice balance of chaos and order - a.k.a. creativity?