Initial commit.
added some sample code for putting an arrow in.
This is a mostly working 3 link snake that has a 'fixed' head at the inertial frame origin. Something is going wrong with the intergration right now. Also, this is really just a pendulum, since all q's are independent. I think by making them dependent (or at least the internal angles) I would work like the snake.
Have a three link rigid pendulum with an interactive notebook widget attached to animated ellipses.
Didn't have it quite right; when specifying the IC, we need to remember that angles are defined from the previous segment. Probably need to sub in numerical values for the point.pos_from(point2).express(frN).subs(...) expression.
Fixed the visualization using ellipses so angles should be right. Experimented with specifying the internal angles, but no luck yet not making that blow up.
Have a snake that does not have a fixed joint. Currently setup to fall in a gravitational feild with some initial angular velocities. It actually turns.
Added a plot for the COM and took it out of the gravitational field. Looks like, given an initial angular velocity it will not stop moving.
Reordering things to prepare for github
Added stuff from github.