Slow & Fast Math Cats
Little math toy about interactive algebra.
You select the problem throught some drop-downs (Speed of Slow cat, Speed of Fast Cat and Time later) and the program shows the graphic of the 2 lines. And the intersection. The student understand the relationship between problem, graphics, and he can starts the simulation and to look at the evolution of the action.
Use the video as a tutorial.
Video in the mirror site.