Inspector: "Have you been painting?" Jack: "No!" Mary: "Yes you have Jack. You have done all these."
Inspector: "Oh these are nice. Do you know what colour this is?" Jack: "Dunno."
Inspector: "This is green. You get it on traffic lights. How about this? You get it on traffic lights too."
Inspector to Mary: "Never mind, I expect he's had a tiring week."
The inspector departs. Mary is very angry with Jack. "You've known your colours since you were in the infants. Why didn't you tell her?" Jack: "Didn't have to. Anyway, she should know her own colours!" The author is head of a county primary school in Cambridgeshire