Seismic Raytracing Java Demonstration Applet (Cartesian coordinates)
Please allow a few moments for the applet to download and for Java to initialize...Once it's running you can click the green question mark for a brief help listing.
Don't see an applet coming up after a long time, or having difficulty with the applet freezing up? The most likely culprit is that your Java plug-in is too old - go update yourself at java.sun.com/getjava.