I live in a house that's well over a hundred years old, and one of the rubber bumpers from an old doorstop finally just disintegrated from age. I could have gone to a big box store and bought a cheap replacement doorstop, but what's the challenge in that? I used 123D Design to model a replacement bumper that does just what I need. I integrated a flange on the end so that it snaps on just like the original one did. Printed with white NinjaFlex, .3mm layers, has just enough flex but not too much flex.