For my melody study I extended my previous project, an Additive Synth, by adding visualization and control over the synth’s tuning. Each oscillator’s waveform is graphed in a circle. Since all oscillators route through the first oscillator, the top left graph represents the sum of all four - the output waveform.
You can control three synth voices to make chords and switch between Just and Equal temperaments to see and hear how they are different. It is especially noticeable on the tonic chord, in this case A Major. There are audible pulses with Equal temperament, whereas Just temperament produces a smooth harmony. You can clearly see this in the graphs as they go from fluctuating to very even.