This is categorically different from the Gömböc, because it doesn't have uniform density. Most of its mass is concentrated in the base plate.
A new pyramid-like shape always lands the same side up
21–30 of 175 posts
Re: A new pyramid-like shape always lands the same side up
#22Couldn't you achieve this same result with a ball that has one weighted flat side?
And then if it needs to be more polygonal, just reduce the vertices?
Re: A new pyramid-like shape always lands the same side up
#23Couldn't you achieve this same result with a ball that has one weighted flat side? And then if it needs to be more polygonal, just reduce the vertices?
A ball that has one flat side can land on two sides: the round side and the flat side. You can easily verify this by cutting an apple in half and putting one half flat side down and the other flat side up.
Re: A new pyramid-like shape always lands the same side up
#24Couldn't you achieve this same result with a ball that has one weighted flat side? And then if it needs to be more polygonal, just reduce the vertices?
The article acknowledges that roly-poly toys have always worked, but in this case they were looking for polyhedra with entirely flat surfaces.
Re: A new pyramid-like shape always lands the same side up
#25A reminder that simple inventions are still possible.
Simple invention made possible by sophisticated precision manufacturing.
I think it is a very underestimated aspect of how "simple" inventions came out so late.
An interesting one is the bicycle. The bicycle we all know (safety bicycle) is deceivingly advanced technology, with pneumatic tires, metal tube frame, chain and sprocket, etc... there is no way it could have been done much earlier. It needs precision manufacturing as well as strong and lightweight materials for such a "simple" idea to make sense.
It also works for science, for example, general relativity would have never been discovered if it wasn't for precise measurements as the problem with Newtonian gravity would have never been apparent. And precise measurement requires precise instrument, which require precise manufacturing, which require good materials, etc...
For this pyramid, not only the physical part required advanced manufacturing, but they did a computer search for the shape, and a computer is the ultimate precision manufacturing, we are working at the atom level here!
Re: A new pyramid-like shape always lands the same side up
#26Worst 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 struc…
> A structure like that would be useful as a tamper detector.
Why does it need to be a polyhedron?
Re: A new pyramid-like shape always lands the same side up
#27Somewhat disappointing that it won’t work with uniform density. More surprising it needed such massive variation in density and couldn’t just be 3d printed from one material with holes in.
Yeah isn’t this just like those toys with a heavy bottom that always end up standing straight up.
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Re: A new pyramid-like shape always lands the same side up
#28Somewhat disappointing that it won’t work with uniform density. More surprising it needed such massive variation in density and couldn’t just be 3d printed from one material with holes in.
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Re: A new pyramid-like shape always lands the same side up
#29[flagged]
Re: A new pyramid-like shape always lands the same side up
#30Worst 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 struc…
> A structure like that would be useful as a tamper detector. Why does it need to be a polyhedron?
I was thinking exactly two stable states. Presumably you could have a sphere with the light end and heavy end having flats on them which might work as well. The tamper requirement I've worked with in the past needs strong guarantees about exactly two states[1] "not tampered" and "tampered". In any situation you'd need to ensure that the transition from one state to the other was always possible.
That was where my mind went when thinking about the article.
[1] The spec in question specifically did not allow for the situation of being in one state, and not being in that one state as the two states. Which had to do about traceability.