Here's a simple example that solves the equations of
motion for a bunch of particles and makes a real-time
plot using Tkinter.   Also uses Python shadow classes.
It's little rough since I cooked up in an afternoon,
but you get the idea.

The Tkinter interface is a little flaky (at least on my 
machine).  Sometimes the particles come up and the
disappear forever.  If this happens, try running it
again and the problem might go away....


