But these all have some learning curve and often use clever tricks ... There are two sine waves and we mix them together to get a sine wave that would decompose into the sum and their difference ...

have the same curve only shifted along the x-axis have an amplitude (half the distance between the maximum and minimum values) of 1 have a period (size of one wave) of 360˚ ...

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.