z - Restarts the action
p - pauses the action
n / m - slow down / speed up the action
w / a / s / d - move your character up / left / down / right

List of changes made by Nathan to get this up to date:
- renamed framerate to frameRate b/c apparently that changed since 2003
- renamed the loop() function to draw() and activated it by adding "loop();" to the end of the setup() function. Again, it's just a change in Processing's format since '03.
- renamed the "Radius" variable to "NukeRadius" b/c it seems like "Radius" is now some kind of internal/automatic variable in Processing. The text was blue in the IDE, which is usually only the case with automatic variables like mouseX

List of new features added by Nathan:
- made the minimum number of people 200 instead of 4000.
- added p as a key that will pause and unpause the action
- added n and m as keys that will slow down and speed up the action, respectively