Nice! Andrej Bauer has implemented the Hydra Game in a Java applet. The Hydra Game, like Goodstein sequences, is a way of coding ordinals ≤ ε0 … hence they provide independence results from Peano Arithmetic. Andrej has all the deets. (A Java applet for Goodstein sequences is here.)
As far as I remember, Ghent University mathematicians implemented an extensive programme which draws the hydras starting from any give hydra some three years ago. I can fins out details if necessary.Andrey Bovykin