AI-assisted proof of optimal packing for 11 squares

(github.com)

79 points | by bluepeter 4 hours ago ago

36 comments

  • dkural an hour ago ago

    It is not as arbitrary or ugly as it may seem at first - see the image here and the explanation: https://x.com/davidmbudden/status/2107646435659481548

  • yzydserd 3 hours ago ago

    fwiw The prime site for square in square packing is at https://kingbird.myphotos.cc/packing/squares_in_squares.html

    The triangular view is most interesting. And a 20 minute video on this view is at https://youtu.be/uL5wuiy34rs

    • pinkmuffinere an hour ago ago

      This is cool! Something seems broken in the representation for 1850 and 1765, squares are strangely intersecting.

      edit: Or maybe something wrong with the way my browser (brave) is rendering it.

    • woah 2 hours ago ago

      Can someone explain why 83 and 87 can't get any smaller?

      • entropicdrifter 2 hours ago ago

        Because the outer perimeter must be a square. 83 and 87 could shrink the outer perimeter in one dimension, but not in both at the same time.

      • sheept 2 hours ago ago

        It is possible they can; it’s not yet proven that the listed packings for 83 and 87 are optimal.

      • danbruc 2 hours ago ago

        Which of the blocks do you think you could move to shrink the solution? Or are you thinking of a completely different arrangement?

      • nemomarx 2 hours ago ago

        They got updated to be smaller this year, so maybe there's still more gains to be had?

    • schiffern 3 hours ago ago
    • Buttons840 3 hours ago ago

      "God is dead and the optimal packing of squares killed him." I will never not think of this meme when looking at these horrors. I see it, but I don't like it. ;)

  • WithinReason 3 hours ago ago

    A list of many square packings, with images:

    https://jlevy.github.io/squares/

    • aunty_helen 3 hours ago ago

      I like geometry. These packings show there are ugly numbers, like 51.

      • s0rce 35 minutes ago ago

        heh, 105 is a mess

  • agnishom 4 hours ago ago

    The readme has no figures :( describing the packing?

  • dekhn an hour ago ago

    One of the greatest classes I ever took was "Cybernetics", taught by David Huffman ("the" Huffman). he started out the very first day talking about information theory, into sphere packing, and on to applications of sphere packing to communications.

    I distinctly remember him concluded with something like "Sphere packing is hard, except in 11 dimenions" or something like that, but when I look at the history, I can't see how he knew that in 1994?

  • mlmonkey 3 hours ago ago
    • brabel 2 hours ago ago

      It’s unintuitive that a messy configuration of squares can be more optimal than neatly arranging them aligned. And by looking at all the current best solutions it does appear that the neat configurations are usually the best , but not always. How does one explain the messy cases?? Is that about how division can result in irrational numbers, and when the number of optimal squares approach one you end up with the messy squares?

  • derektank an hour ago ago

    So this is a proof that the Walter Trump packing is the optimal packing?

  • kevinwang 2 hours ago ago

    Wow, I never would have imagined one could prove optimality for that accursed beautiful thing.

  • coppercrisp62 4 hours ago ago

    Did an interval-arithmetic branch and bound once, getting the rounding modes right took me weeks.

  • reader9274 3 hours ago ago

    Another interesting video related to these types of problems: https://youtu.be/mVH7OPx4QZU

  • rfgplk 3 hours ago ago

    Isn't this obvious? Why do you need a proof for it, just stack the cubes next to each other? If we're talking infinitesimally thin squares, then stack them on top of each other? Am I missing something?

    • raincole 3 hours ago ago

      It takes less time for you to try to read about the question than to type this comment. I know the link doesn't contain visualization, but... come on.

    • 233mhz 3 hours ago ago

      The whole point is that you can fit more than by naively stacking them...

      • DoctorOetker 9 minutes ago ago

        parent is changing the problem by suggesting to "pack in the 3rd dimension": lay all the squares on the same square footprint, resulting in always needing only a square with side length 1 on which all the needed "packed" unit squares are laid.

    • AlexandrB 3 hours ago ago

      Look at some of the other links people have posted for optimal packings. The optimal 11 square packing looks nothing like what you're describing ("just stack the cubes next to each other").