Comet clears the kitchen table and sets out cardboard, a ruler and the measuring jug. "Your turn to run the shop."
"Three parts," Wren says. "A model at a scale you choose, a plan with a density, and a volume check."
"What do you notice about the order?" Comet asks. "Model first, so the plan has numbers to use."
Nova projects a small checklist. "Would you like a hint? Write every measurement before you compute anything."
"And explain each step to your family as you go," Wren says. "If they can follow it, the geometry is right."
"Our designer," Comet says, "this is the whole course in one afternoon. Run it."
Shop Day complete, designer. Twelve weeks, one set, and a Shop Book full of checked measurements. Well built.