It is possible to move the wave source generating the wave and the position of the observer to a desired positionYou can control the time of occurrence of the source.You can also move the source and viewers.Check the Doppler effect by generating a source and moving the source towards or away from the observer.You can also see the Doppler effect by moving the observer.I made a sound when the wave and the observer collided. Even if you only hear the sound, you can experience the Doppler effect.