Swim - the game
Dan Ha recently uploaded a fantastic game called Swim, that he built with Nicole Roach and Cameron Teitelman. Complete with nicely-illustrated instructions! When I asked him about it, Dan said:
The sketch was designed for our CS147 class at Stanford University: Human-Computer Interaction. We designed it the sketch with the goal of creating a simple, fun game that would give kids an intuitive sense of physics. The fish and turtle serve as a metaphor for vectors - the size and orientation of the fish projectiles represent the magnitude and direction of a vector. When they collide with the turtle, the resulting direction and distance that it moves is the combined vector of all the fish projectiles.
Check out this full-screen version of Swim. Below the canvas, you'll see the latest revision of their source code, complete with Processing syntax highlighting.
Great work, team!