It looks like many of these show a construction which you have to follow the details of to check that there aren't gaps or overlaps. Is there a way of checking these automatically? Eg if you can tile a certain amount of space without gaps then it must be able to continue forever? Or can you write down a vector expression for the location of each shape and show finitely that you have exactly covered all lattice points…
Which hypercube unfoldings tile space?
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Re: Which hypercube unfoldings tile space?
#22It looks like many of these show a construction which you have to follow the details of to check that there aren't gaps or overlaps. Is there a way of checking these automatically? Eg if you can tile a certain amount of space without gaps then it must be able to continue forever? Or can you write down a vector expression for the location of each shape and show finitely that you have exactly covered all lattice points…
Re: Which hypercube unfoldings tile space?
#23So it turns out to be all 261 of them? Suspicious.
Yes; I wonder if the same result applies in even higher dimensions? Do all nets of the 5-cube tile 4-space, etc. There is a proof on WHUTS that all 261 nets of the 4-cube can, but is a proof by exhaustion (i.e. try every net in an automated manner and see if it is possible), this may be possible to do for the 5-cube nets (9694 possibilities), and 6-cube nets (502110 possibilities), but starts to look difficult in hig…
I'd like to set a notification for when some hero of future-geometry solves this in ten years.
Re: Which hypercube unfoldings tile space?
#24many folding solutions are Minecraft screenshots. e.g. https://whuts.org/unfolding/124 We are living in a very interesting time
Re: Which hypercube unfoldings tile space?
#251. The community solved it really fast, within a day or three, but a single programmer solved it even faster [1]. You could also argue that it was the month or so [2] making the website that led to the solution.
2. It was really common to use Minecraft to visualize the solution [3]. I think this speaks to the benefit of tools that make it very easy to manipulate and visualize a system [4].
[1]: https://mathoverflow.net/questions/199097/which-unfoldings-o...
[2] https://twitter.com/oliverdunk_/status/1393366708652548114
[3] https://twitter.com/standupmaths/status/1393516840232624133
[4] Just... any Brett Victor video. e.g. http://worrydream.com/MediaForThinkingTheUnthinkable/
Re: Which hypercube unfoldings tile space?
#26What about combining the tiles?
The Math overflow answer which provides tilings for all possible nets (https://mathoverflow.net/questions/199097/which-unfoldings-o...) gives two which fit exactly into a 4 by 4 by 2 box - https://mo271.github.io/mo/198722/tilings/plots/72.html and https://mo271.github.io/mo/198722/tilings/plots/159.html. Since a 4 by 3 by 2 box can fill 3D space on it's own, you could alternate boxes using different nets.
It's a bit of a cheat though. I would strongly suspect that there are better ways to do it!
Re: Which hypercube unfoldings tile space?
#27Re: Which hypercube unfoldings tile space?
#28Earlier quoted context omitted.
What other tools are good for this sort of representation? Geogebra??
There are a number of examples using Blender. Finally the default cube is useful.
I was thinking Mathematica or similar might have more useful 3D shape representations?
Re: Which hypercube unfoldings tile space?
#29Is there an example of 8 cubes that are proven to not tile space?
Re: Which hypercube unfoldings tile space?
#30On the topic of 4D and tiling stuff, the 24-cell is a platonic solid that tiles 4D space, with some interesting cross sections that tile 3D space: https://en.wikipedia.org/wiki/24-cell_honeycomb#Cross-sectio... There is no 3D equivalent of the 24-cell, but two of the cross sections (rhombic dodecahedron and bitruncated cube) hint at what that "missing" platonic solid would look like.
Its so hard to grasp that in all the pictures its basically the same object, just viewed from different angle.