Pascals Triangle as a Galton Board
Visual proof that each number in Pascal's Triangle represents the number of paths to that location, using a model of a Galton Board or "bean machine" to demonstrate. See a discussion and demonstration in this Mechanical Scribe post.
Just open demo.html. You don't even need to run a server! Then hit "Start."
Too slow? You can set the parameters here and reduce the timing of the ball drops or randomize the order of the paths.