todo.txt

- complete tests
  - make the roulette2 tests similar to roulette1

  - do nice plots for all tests
      - add in a "line" from N to M to make the rotation more obvious

  - use similar to create animations
      - need to do gif script

- any other curves for roulette examples?
   http://www.2dcurves.com/roulette/roulette.html
   http://en.wikipedia.org/wiki/Roulette_%28curve%29
   http://140.177.205.23/Roulette.html
      hyperbola on a line, tracking the center, gives rectangular elastica
      generally, tracking centre of a conic, get "Roulette de Sturm"
         http://www.mathcurve.com/courbes2d/sturm/sturm.shtml
      hyperbolic spiral
      logarithmic spiral
   also see Walker's paper

   some of the "weird wheel curves"

- add in routines for
   - glisettes
   - pedal curves