Harmonic Table note Layout: Wicki Hayden layout, Isomorphic keyboard, Leonhard Euler, Perfect fifth, Major third, Diminished fourth

Augmented Fifth: Classical music, Western culture, Perfect fifth, Semitone, Diminished fourth, Enharmonic

Major Chord: Music theory, third, Perfect fifth, seventh chord, Interval (music), Minor third

Major Third: Classical music, Western culture, Interval (music), Staff Diminished third

Leonhard euler, un genie des lumieres