
Kula Ring - Artistry121
https://en.wikipedia.org/wiki/Kula_ring
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btilly
Sounds familiar.

Ah, yes.
[https://en.wikipedia.org/wiki/Doorways_in_the_Sand](https://en.wikipedia.org/wiki/Doorways_in_the_Sand)
had an interstellar version of one as a plot point. :-)

~~~
MikeNomad
Heh. "Doorways" was the first thing I thought of when I saw the article's
title. Doorways was excellent prep reading for grad school.

