Stoll runs kleinbottle.com and sells glass Klein bottles. The site is great and full of descriptions of his hacks and automations for his business. I bought a

Stoll runs kleinbottle.com and sells glass Klein bottles. The site is great and full of descriptions of his hacks and automations for his business. I bought a bottle and it came with free stickers and a wonderful set of instructions full of all the topological puns I could want.