QGolf is a program that simulates how a wave can travel through a rope, when there is a signal (or a puls) at one end. Forces cause this disturbance to travel (or to be transmitted) via the rope. It can clearly demonstrate various properties of waves, like resonance and the coexistance of two travelling pulses on one rope.
Since pictures are more worth then text, here are some screenshots:
A puls is generated and travels through the rope from left to right.
Wave is reflected by the far end (or right end) of the rope.
Manipulate the simulator in real-time. Or in simulated time.
Two waves, each in opposite direction, can pass through each other.
You will need the (free) Qt library to compile it. You can download this here.