3 ms·

I don't have a source, but the analogy seems obvious to me. If you're more curious, I guess you could do your own research?

• sverige 9y ago
  I have, actually. I can't find a reliable source for the origin of the name, even in the original papers written to describe them.
• fjsolwmv 9y ago
  There's no need to comment if you aren't sharing any information or ideas.