15 Great Circles

-

Last weeks Math Monday article showed the intersection of 4,5 and 6 great circles made using CDs and left the reader with a challenge to assemble a model of 15 intersecting great spheres, well challenge accepted.

I used a 3D modelling program to subdivide a dodecahedron, which gave me points in the middle of each face and the middle of each edge. From there I reconstructed the basic triangular 'unit' and once I had the required angles I used inkscape to add the great circle outline to the model. Perhaps a complicated route but it works. (svg here)

Oh yeah, and maths is beautiful
 275/286




Each 'unit' of the sphere was made from 2 pieces of card so each edge of the final model is exactly 2 pieces of card thick and no more this makes the whole construction quite sturdy.










Popular posts from this blog

Wiring the Ruida Controller

-
Image
The RDC6442G controller from Ruida This is going to be quite an image heavy post describing the rewiring needed to convert between the Leetro controller and the Ruida controller. It is also pretty straight forward on the old Just Add Sharks laser cutters because all of the wires are clearly labelled. The controller was prepared in the previous step in order to make this conversion process as smooth as possible. The Leetro (Pad03) panel on the left and the Ruida panel on the right The view from inside the laser looking up at the control panel The control panel is an easy place to start, both panels have just a single cable that runs down to the controller, both panels are a very similar size, with the Ruida panel being slightly smaller underneath so it will fit in the hole left behind easily. The Pad03 panel clips into place so you'll need to reach up inside the machine to work the clips loose. The cable runs down the inside of the laser and is cable tied onto mounti...
Read more

Rainbow Puzzle Box

-
Image
This is a binary sequence puzzle box built from 3mm birch plywood, it uses a Gray code pattern to ultimately align all the dials into a rainbow pattern before the lid can be removed. It's actually a redesign of a puzzle inside Loki's box of Tricks  because I thought it would make a cool stand alone puzzle box. The files are available for sale in my Etsy store . ( svg here ) The puzzle consists of five interlocking disks that can only rotate when the disks either side of it are in the correct position to allow it. The large wheel in the middle and the disks on the underside of the lid further restrict the rotation of the disks. The large wheel must be pointed to the disk that is being rotated and the large wheel is in turn restricted from pointing to the smaller disks depending on alignment. Once all the disks are aligned into the full rainbow the large wheel is completely free to rotate and can be turned to the edge of the box and allows the lid to be removed. There is a very ...
Read more

Laser Cut Cryptex

-
Image
This is my laser cut cryptex. It features 28 different characters and 9 rings, giving a total possible 10.5 Trillion different combinations. I took a bit of time developing the design so that I could add some nice features. This cryptex file is laid out so that you can have any number of rings in your own design. The best feature is that the codeword is changeable, each locking ring has an outer letter ring that can be placed in any one of the 28 different positions. Once the rings are back in place the ring locking bars can added and they prevent the rings from being modified until the box is open again. It's a bit hard to explain so I made a video showing how it all work ( svg here ) It took a long time to assemble this so I lived with my initial design choices but if I were to remake it I would adjust the file to make the ring locking bars out of 6mm ply and maybe put some blind holes onto the code rings to prevent the code being brute forced.
Read more