First week of school holidays. I get up and thank Archie for letting mummy sleep in so late. Archie suggests reward for himself - game of badminton for us in the rain but we agree instead to drawing undersea tableaux. Assemble large piece of paper, coloured pencils and sticker book of sea creatures for inspiration. Agree Archie will draw shark with me assigned to humble cowfish. Unfortunately forego discussion on scale and upset erupts when we realise Cowfish is much bigger than shark, not reflecting reality. I explain perspective — that maybe Cowfish is closer to us and shark off in background. Explanation makes thing worse. Shark meant to be major player, capable of eating Cowfish. Explain again principles of perspective. Ruby is laughing. Archie is angry at older sister laughing, after all what is so funny? Send Ruby to bedroom. Agree to begin new undersea tableaux where shark is major player. Careful to check specifications for new Cowfish. Cowfish gets axe. Further clarification...