Customizable Braiding Star

This is a nice tool for knitting braids. It is fully customizable
(number of spikes, size, yarn thickness etc.)

How to use (for the 8 spike star):

* Take 7 strands of yarn, tie them together and fix them in the slots
of the star.
* Count 3 slots to the right of the empty slot and place the yarn
which is there into the empty slot.
* Repeat the last step with the new empty slot.

Using a different number of spikes and a different slot count from the
empty slot will result in a different pattern in the braid.

Also published on github: https://github.com/ohitz/3d-models/