Generating Signals with GoldWave

Here is a screenshot of a 400Hz sine wave with 8 cycles.

When we add harmonics, this is the expression that would be used.

A 3rd Harmonic

As you can see when harmonics are added the wavelength starts to change shape.

A 5th Harmonic

A 7th Harmonic

A 9th Harmonic

After adding more harmonics the expression generator now looks likes this: 

The wave is gradually taking on a square shape.

If you look at the wave through the spectrum filter you can view the frequency content of the waveform.
The Magnitude Spectrum.