@cstross Sounds like Larry Niven, though I've read all the Ringworld, I've not read the smoke-ring book.

Ringworld and Dyson Spheres need magic anyway.

Easier to make a Mobius strip at home than a Klein bottle. Fun to cut in half, twice.

@cstross perhaps warm up with a mobius strip space station first?

Rotating of course, so subjective gravity inverts when you do a lap.

@cstross Make it 4D and you're back to the seelie and unseelie courts. (But the unseelie have the seelie's umbrellas...)

@cstross a pity Richard Lupoff has passed, this sounds like a worthy companion to Circumpolar!

https://en.wikipedia.org/wiki/Circumpolar!

Back in high school math we had a series of posters up showing the Earth remapped onto various geometries and genuses - done with styrofoam and paint given the tech of the times. I managed to obtain my own copies, decades later.

@cstross

You'll need to embed the earth in 4-dimensional (or higher) space to do that, instead of the usual 3-dimensional space. So you'll want to also distinguish the consequences of the additional needed dimension from the properties due to the Klein bottle itself.

@cstross
Surely that is just another flat earth theory trying to get around the edge problem?

@cstross reality: It's an Ezra Klein bottle

@cstross could it be mixed with Christopher Priest's Inverted World ?

@cstross incidentally, @Kroc is writing a novel on a Psion 5mx, in which the world is within a giant sand hourglass, and it's slowly running out... (in between writing a truly cool new text editor for EPOC...) :-)

@cstross ah yes and there are conspiratorial “round earthers” who won’t accept the truth

@cstross that sounds like one of the weirder Xeelee series stories

@cstross As long as there are still C.H.U.Ds...

@cstross

A very groß klein bottle 😜

@cstross nothing would surprise me nowadays