Using a copy of [SPICE] a free circuit simulation application, I have created several sine wave sources and summed them together. Seen here, the waves combine into a square wave with it looking ...

as are water waves. A hand qucikly moved up to continue the sine wave motion in the rope. The waves travel from left to right, and the particles of the rope vibrate vertically. In the diagram ...

The representation of a PERIODIC sound or WAVEFORM as a sum of Fourier components (i.e. pure SINUSOIDAL WAVEs). According to the FOURIER THEOREM, periodic sound may be shown to consist of SINE WAVEs ...

Sine-wave speech can be thought of as a sort of auditory illusion, a sensory edge case in which one’s experience has a clear “before” and “after” moment, like going through a one-way door.