This page contains three Java applets. Two of them are JSPs and the
third is an applet connecting these together.
In the smaller JSP applet you have two points (a,b) and (c,d)
which you can drag. The larger JSP shows a direction field of a system
of two linear differential equations, where the coefficients are determined
by points (a,b) and (c,d).
Before you can connect these JSPs together, you should wait until both of them have been loaded. Then you can connect them simply by pressing the "Connect" button.