Sit down. Take an end. Nothing has to be said.
Every page has one track and two ends. You start at one, they start at the other, and you meet somewhere in the middle. Or you do not, and that is also fine.
Between the tracks are doodle pages made for two: shapes to close, a pattern to carry on, a box to make dark each, a word to colour in one letter at a time, half a shape for them to finish. No questions about the day. No turns. Nothing to finish and nothing to show anybody afterwards.
For the twenty minutes when neither of you has anything left. The book runs in four parts, one each, take turns, meet in the middle, whatever you like, so it goes from side by side to together without anyone having to say so.
Sixty-four pages, 190 mm square paperback. For a grown-up and a child together, ages 3 to 8. From the Doodle range at The Regulated Human Co. Regulation before optimisation.