He's designing a board game - much more deliberately than I ever did as a kid. He started with notes on paper and has everything calculated out, from how many action cards of each type to how many squares to how to make the game challenging without it feeling too hard.
Yesterday my 11yo went into work with Dad and it was just these two home for the day. They made themselves this picnic lunch.
I love having smaller combinations of kids - they play differently on their own, including after their brother got home from school. And my oldest loved being a big kid at work all day.