There were two main challenges in the prototype:
- Figuring how to evenly distribute 6 points around a central point
- Devising a central axis that can increase and decrease in length as the model twists
![Prototype extended](/lego/assets/images/hyperboloid/prototype-extended_400.jpg)
![Prototype collapsed](/lego/assets/images/hyperboloid/prototype-collapsed_400.jpg)
![Prototype from above](/lego/assets/images/hyperboloid/prototype-from-above_400.jpg)
(Gotta love universal joints.)
The final model uses 32L axles and 11 x 11 gear racks (major kudos to the author of this article about its geometry):
![Model extended](/lego/assets/images/hyperboloid/extended_400.jpg)
![Model collapsed](/lego/assets/images/hyperboloid/collapsed_400.jpg)
![Model from above](/lego/assets/images/hyperboloid/from-above_400.jpg)
Video of the final model: