Poincaré was an early project on interactive geometry. I’d been teaching a course on euclidean and inversive geometry using complex numbers as coordinates. In the last section of that course, we discussed the Poincaré universe, a well-known model of hyperbolic geometry. With the help of a small grant (a one-course teaching release, if I remember correctly), I was to develop an online module for this section.

This was in 1997 or thereabouts. Like everyone else developing online educational materials at the time, I was completely naive about the amount of work involved and the time necessary to complete that work, not to mention the major difficulties with coaxing the software of the day to do what I wanted it to. Needless to say, only a small part of my ambitious project was completed in the allotted time and, though I continued to work on the project later, I left the university, so none of the materials were ever actually used in the course.

Later, I re-purposed the materials I did produce as a demo of what could be accomplished, given much more time and more appropriate technology. I showed the demo at an educational technology conference, combined with another of my projects, the BinderBaby notebook interface.

The pages here are mostly an archival description of the project, though much of the project still works as described. There are pages on:

• the mathematics underlying the Poincaré universe module
• some of the visual aspects of the design (panels, math text)
• the use of Geometer’s Sketchpad to make the geometry interactive
• the interactive tools I built for working with Poincaré geometry.