Additionally, in sound, there are ways to create depth. The quieter the sound is, the more it seems like it is far away, especially if the original sound is usually much louder. Also, pitch changes based on if you are in front of or behind it. (Imagine a truck racing by, blaring its horn. It goes from a higher pitch to a lower pitch as it passes you.) Also, ears perceive sound in stereo (through both ears) to perceive where the sound originates based on when it gets to both ears. If a sound is on the left, it will get to the left ear louder and slightly faster than it will to the right. I could use these components to create "moving music", or a song that seems to be moving in space, while the listener is sitting still.