This video describes how to use Zen Magnets to build a hollow diagonal cube using Mathnetism's ingenious technique (see https://youtu.be/stZyv-_H8IU and https://youtu.be/b-GQd_km0aA). The shape has double-thickness walls and is amazingly strong. For edge lengths n equal to 2 or larger, the shape requires a total magnet count of N = 24n(n-1)+14, giving: n, N 2, 62 3, 158 4, 302 5, 494 6, 734 7, 1022 8, 1358 9, 1742 10, 2174 11, 2654 12, 3182 13, 3758 14, 4382 15, 5054 16, 5774 17, 6542 18, 7358 19, 8222 20, 9134 21, 10094 22, 11102 23, 12158 24, 13262 25, 14414 26, 15614 27, 16862 28, 18158 29, 19502 30, 20894 Shown in the video are cubes of edge length 5 (494 magnets) and edge length 20 (9134 magnets). The magnet count equation was derived by subtracting the magnet count of a solid diagonal cube of edge length n-2 from that of a solid diagonal cube of edge length n, that is, by hollowing out a solid cube and seeing how many magnets are left. For more information about solid diagonal cubes, see https://youtu.be/VMGpfXAByW4.