The shape of the hollow space inside an assembled Tetraxis toy is called a rhombic dodecahedron.
You can see that the locations of those circles are the corners of the red rectangle we started with.
If you cut this larger rhombus out of paper, you can then fold it along the dotted lines and tape it together to make the shape of a single Tetraxis stick.
The circles indicate the location of the magnets.
Put 9 rhombuses together to make one larger rhombus, and add circles at the centers of 4 of the smaller rhombuses.
Start with a cube.
Look at this red plane inside the cube.
These are the dimensions
of the rectangle.
Inscribe a rhombus in the rectangle.
The Rhombus in a Rhombic Dodecahedron
Can you figure out the angles between any two sides of a Tetraxis stick?
When folding you have a choice of whether to make the dotted lines be on the inside or the outside of the sticks. If you try it each way, you get two sticks that are mirror images of each another. With 12 of each kind of stick, you can build two assembled Tetraxis puzzles that also are mirror images of each other.
Cut on the solid lines.
Fold on the dotted lines.
Click on the image to get a file you can print out.
The mission of Girls’ Angle is to foster and nurture girls' interest in mathematics and help improve K-12 math education.
This video was made using Blender, a powerful, free, open source 3D creation suite. (www.blender.org)
“Tetraxis Geometry” was created and produced by Girls' Angle,
a math club for girls that meets in Cambridge, Massachusetts.