tetraxis

Held together with 48 rare earth magnets, this object is made up of 12 identical sticks of wood surrounding a hollow center. The cross-section of a stick is an equilateral triangle. As can be seen in the video link below, once the sticks are taken apart, reassembly is much easier than you might expect. This is because the magnets guide the pieces into position, and the overall symmetry of the structure is such that any two sticks that make contact relate to each other (and the whole object) in exactly the same way:

tetraxis and six axis sticks

bronze

tetraxis star

six axis

bronze star

click on this photo to see a video:

This design, or more accurately, the discovery of the structure of this object, was made by John Kostick. As shown below in bronze wire, the folding 4-axis and 6-axis stars were two of the many star structures he first started making and marketing in the mid 1960’s.

Each wooden stick in the puzzle corresponds to one of the 12 wires in the 4-axis, or “tetraxis” star.

In 2009, we created large versions of these puzzles for the Math Midway, which made its debut at the World Science Festival Street Fair in NYC in June. It’s a carnival-style traveling exhibition of The Museum of Mathematics ( momath.org ) that provides an interactive, hands-on tour of mathematical concepts.

Click on the above picture to link to a video of the Tetraxis being assembled.

Just as John’s bronze tetraxis star can be built out of sticks with an equilateral triangular cross-section, the configuration of wires in a six axis star can similarly be made so that each wire fills out the isosceles triangular space it passes through.

The cross-section of the stick needs to be a 108°- 36°- 36° triangle.

Each of the 30 sticks (5 pointing in each of the 6 directions) is identical.

Click on the picture above to link to a video.

Now here are some images of small wooden ones. The diameter is about 3 inches.

Wooden objects like these, in both 3” and 4” scale, as well as the bronze stars on which their design is based, are available for purchase by contacting us.