Sonar Display Screen This Sonar Display is comprised of a "waterfall," many sound waves arranged vertically. Scrolling upwards, these waves represent different sound patterns over time. Moving horizontally across the screen one can read the sound waves for different directions. Remember, when in a submarine one must think up and down as well as left and right. Sonar technicians are able to look at the sound waves and identify their source with extreme accuracy. Constantly watching the screen for a "contact," a sound pattern other than background noise, these technicians must rely on their own skill rather than computers to correctly identify the source of any contact. Diagram reprinted from Tom Clancy's Submarine: A Guided Tour Inside a Nuclear Warship, Laura Deninno, Series Illustrator.