Frog Walk javascript program, by Jeffrey Rosenthal, related to this book. Description at the bottom.

This program simulates the "frog walk" Markov chain: on each step it either stays still, or moves one space clockwise, or one space counterclockwise, each with probability 1/3. The frog's current position is shown in green. Keyboard shortcuts (you might need to click on the canvas first): '0-9' to change the simulation speed ('1' for one-step-at-a-time), or '+' or '-' to increase/decrease the number of states shown, or 'p' or 'm' to increase/decrease the current state, or 'r' to restart.

This program is written by Jeffrey Rosenthal. See also my other JavaScript, my Stochastic Processes book, and my Java Applets.