Reflection, Superposition, and Resonance on a String

When reflections is set to zero, only the original wave shows. When reflections is set, for instance, to 2, the original wave, its reflection from the right end, and the reflection of that from the left end all show in green. The sum shows in black. Damping controls how much of the wave is absorbed at each reflection: 1 is perfect reflection and 0 is perfect absorption (so perhaps I should have called it reflectivity). The triangle in the bottom left with run the animation, or you can drag or click and arrow-key the t slider to advance time manually. Point B is movable. How does the size of the sum wave depend upon B's position?