The main output controls the overall volume.

The vertical sliders control the mix of harmonics.

The frequency can be changed by typing on your keyboard.

The frequency control layout can change between piano style and guitar style.

Sine wave mixer: add sine waves together to create complex waveforms.

Each number n is the nth harmonic.

The ø button inverts the phase.

Would need cosine sliders and/or continuous phase controls to create more varieties of waveforms.