The applet appears below but you will probably want either to look at the Instructions (they'll pop up in a new window), if you are already familiar with the basics of phase equilibria, or the Tutorial for a step-by-step introduction to all the concepts involved.
This example has four phases (A, B, C, D; B is the most "liquid-like") and includes an invariant point, several univariant reactions, coincidences, and singular points. You might want to begin with a simpler example with only two solids, a liquid, and one eutectic reaction.
Send suggestions, whines, and flames to Paul Asimow.