GGG, my son going to preschool for almost a month and in this month, what he do the most is writing too!!! Before he went to preschool, he keep writing number, and now he write numbers and letters (and some simple words that he can spell e.g. ten, nine, one), he also write some "words" that make up by his own and pretend saying english. I feel like his brain is overwhelm after attending the school, and he seems processing the English right now...
He used to play board games, lego, smart games with me, but now he refuse to play them all, just writing.... =_=