No discussion of Klein bottles would be complete without mentioning Cliff Stoll's Acme Klein Bottle company.

https://www.kleinbottle.com/

His warehouse is pretty unique: https://youtu.be/-k3mVnRlQLU

I ordered a small Klein bottle from him, and the best part wasn't even the bottle I eventually received. It was the emails he sent me as he prepared the shipment, along with photos of him wrapping the bottle, his wife's garden, the bike he rides to the post office. Second best thing was the hand-written note he included thanking me for the order. Third best thing is the bottle itself, but honestly, it's just another knick-knack on my shelf.

I had the same thought, he cherishes making you laugh and having a good and interactive experience. He has different jokes for every country.

When I received my Klein bottle, along came some papers from ACME with numbers and instructions. The delightful inside baseball cane when he had a field for "number of ingredients in Licor 43"!

Yes! I run this zero-volume business for fun ... and the joy of meeting interesting people. So your note brings a broad smile to this tired astronomer's face. Thank yoU!

Similar story. Ordered one for my wife. Also recommend watching him on YT (Numberphile).

I just bought one and he emailed within an hour and shipped within two. The photos and conversation were lovely. He's a role model.

His warehouse is amazing. It's cooler than the Klein bottles. This guy is like a real Doc Brown with too much time on his hands.

I'm pretty sure I say this every time Cliff Stoll is mentioned on HN, but one of my goals in life is to be as excited about something as Cliff is about everything.

... naturally, I'm a day late to this note. All the same, it's worth mentioning that I feel like I'm a member of the HN tribe, although it's been many years since I"ve really done much creative hacking. All the same, I deeply appreciate the kindness & joy that HN people pass along. Oh, there are a still few niches where techno-oddballs are appreciated.

Warm wishes, -Cliff

And four days later, the conic loaf of bread video Brady just posted is perhaps the best example yet of the level of excitement that I'm shooting for pretty much anywhere in my life (and you've found it in bread...)

A mathematician named Klein

Thought the Mobius band was divine.

Said he, "If you glue

The edges of two,

You'll get a weird bottle like mine.

—-

David Pleacher (https://www.pleacher.com/mp/mpoetry/klein.html)

The video on that page is a great explanation. Very well stated, demonstrated and produced.

"In the end, I am very proud of the illustrations I came up with.’

Rightfully so. These are easily the best visual explanations of the Klein bottle I have seen.