Earlier in feature request 19. Pedro mentioned the Harmonic and Linear keyboard layouts. The linear being simply all the tones ina row, and the harmonic making it easier to make chords.
I made a synthesis of each, that fits in a standard keyboard.
If you go diagonally down from top left to bottom (i.e. 1-z), it is half-tones like linear. If you go diagonally from top right to bottom (i.e. 5-x) it is minor thirds 3-half-tones. If you go horizontally across it is major thirds 4-half-tones.
Meaning it is easy to construct chords.
Major chord is 4half-tone followed by 3half-tone,
wheras minor chord is 3half tone followed by 4 half-tone and so on.