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A new pyramid-like shape always lands the same side up

(www.quantamagazine.org)
598 points robinhouston | 4 comments | 25 Jun 25 20:01 UTC | HN request time: 0.693s | source
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ChuckMcM ◴[25 Jun 25 21:09 UTC] No.44381861[source]▶
Worst D-4 ever! But more seriously, I wonder how closely you could get to an non-uniform mass polyhedra which had 'knife edge' type balance. Which is to say;

1) Construct a polyhedra with uneven weight distribution which is stable on exactly two faces.

2) Make one of those faces much more stable than the other, so if it is on the limited stability face and disturbed, it will switch to the high stability face.

A structure like that would be useful as a tamper detector.

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1. gus_massa ◴[25 Jun 25 23:21 UTC] No.44382719[source]▶
A solid tall cone is quite similar to what you want. I guess it can be tweaked to get a polyhedra.
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2. MPSimmons ◴[25 Jun 25 23:39 UTC] No.44382827[source]▶
A weeble-wobble
3. ChuckMcM ◴[26 Jun 25 00:40 UTC] No.44383158[source]▶
So a cone sitting on its circular base is maximally stable, what position do you put the cone into that is both stable, and if it gets disturbed, even slightly, it reverts to sitting on its base?
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4. iainmerrick ◴[26 Jun 25 04:49 UTC] No.44384271[source]▶
I think you’re overthinking it. The tamper mechanism being proposed is just a thin straight stick standing on its end. Disturb it, it falls over.