Understanding waves better has a wide range of applications. For instance, can help you the same style of thing with sound waves- except, rather than creating a "spout" you basically vibrate a tiny area backwards and forwards a whole lot (while everything nearby only vibrates a little), heating it up. You need to use this to destroy teeny tiny pieces of a person's brain, and never having to cut through their skull together with remaining portion of the brain. https://www.ted.com/talks/yoav_medan_ultrasound_surgery_healing_without_cuts?language=en[1] To ensure that uses ultrasonic speakers around another person's skull in place of paddles around a pool, but the basic principle is the same.
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