The other day, my 4-year-old started to stand on a slick and rickety fiberglass shell chair in the attempts to reach something off of the shelves in his new room set up. I stopped him. He got a bit upset, and I told him the chair was unsafe and that he shouldn't stand on that. I reached quickly for one of the wire-based stool-tables I'd made, and he said, "Dada, you can't stand on a table"... "Ok, fine: I'll make something else..."
The next day, I made the prototype of the Lambda stool in the workshop (pictured here). He's quite happy, and it works well for him, but I already see some improvements for his particular set-up (desk-height step, congruous materials, etc.).