I was looking at 3D printed whistles the other day and wondered how hard it would be to make one that just snaps onto a jacket zipper, so you'd always have a whistle with you. Looked at someone's 3D whistle to come up with basic design, experimented making different size chambers for multiple tones and futzed around with variety of ideas to attach zipper pull vs. easy printing. Spoiler alert, most zipper pulls are 2mm thick and 12mm wide, except all of those that aren't!
#3dPrinting #whistles