Peg-in-hole toys are as old as cave-dwelling ... and TinkerToys.
But corrugated board, [plastic or woodpulp]; a pair of safe-scissors and plastic pegs to fit tightly into the corrugations would be new ... I think.
Some pegs would be straight half-in-half-out joiners; some would be right-angle
bent for walls; others 45degree bent for rooves.
Woops. All those little pegs would be dangerous to little kids. Forget it I thought.
"Hold on," said a kindergarten teacher I showed the pegs-in-edge of-corrugated-board principle to, using beheaded matches.
She played around for while then said, "Look. It's a grown-ups' toy for making your dream house on a tabletop. See. Like this."
Later, I left her and her new husband hacking up bits of board for walls, and using side-cutters to cut pegs from plastic-coated wire.
I felt miffed. They had fried my raw egg of an idea before I'd even cracked it.