After sketching the stool, Feichtner made 1:1 cardboard models stable enough for a person to sit on (pictured). An engineer then nailed down important production details — like draft angles and down forces — generating final rapid-prototyped models to test the stackability and stability of the stool. The model material turned slightly white when distressed, which allowed Feichtner to see where the stool would experience stress when overloaded.