I went to the RMSC recently and found some really cool stuff upstairs. One thing in particular that caught my eye was a water/strobe light display. The way it was set up, there was a window to look through and two dials. one to control the speed of the vibrating hose, and the other to control the speed of the strobe light. When both were aligned just right, the water didn't appear to be moving at all. This was because the speed that the hose was vibrating was the same as the strobe light was blinking, so the light only reflected off the water after that specific time, at which point it was in the same spot as the wave before it had been. These two changes were moving in the same frequency, making one cool interactive display.