A reminder that simple inventions are still possible.
Simple invention made possible by sophisticated precision manufacturing.
A new pyramid-like shape always lands the same side up
11–20 of 175 posts
Re: A new pyramid-like shape always lands the same side up
#12maybe they should build moon landers this shape :-)
Per the article that's what they're working on, but it probably won't be based on tetrahedrons considering the density distribution. Might have curved surfaces.
Re: A new pyramid-like shape always lands the same side up
#13OMG It looks like a cat:)
Re: A new pyramid-like shape always lands the same side up
#14Somewhat 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.
Did they actual prove this?
Re: A new pyramid-like shape always lands the same side up
#15OMG It looks like a cat:)
Re: A new pyramid-like shape always lands the same side up
#16Worst 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.
Re: A new pyramid-like shape always lands the same side up
#17That's not a Platonic solid. Come on, like.
Re: A new pyramid-like shape always lands the same side up
#18Re: A new pyramid-like shape always lands the same side up
#19Somewhat 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.
Did they actual prove this?
They didn't need to, because it was proven in 1969 (J. H. Conway and R. K. Guy, _Stability of polyhedra_, SIAM Rev. 11, 78–82)
Re: A new pyramid-like shape always lands the same side up
#20Somewhat 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.