Nora, having just turned twelve, declared out of the blue one Sunday morning, “Chairs should be triangles.”
Me, “You mean the shape of the seat?”
“No. The whole thing. Triangles are stronger than squares.”
“That’s right. They are. But how do you know that?”
Nora in her “that’s-obvious-duh” tone replied, “That’s just known.”
Some people study mechanical engineering, design, or millennia of furniture history to figure this out. But for some twelve-year-olds, apparently, it is just known.