A DUSTY PHYSICS BOOK read with the intention of defining love or some threads of it:
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Psychoacoustics, among other things, deals with sounds that are close in frequency and produce phantom beat notes.
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A mirror is an object that reflects light or sound in a way that preserves much of its original quality prior to its contact with the mirror. Some mirrors also filter out some wavelengths, while preserving other wavelengths in the reflection.