Newton’s rainbow forms the familiar ROYGBIV because he thought the range of visible colors should be analogous to the seven-note musical scale.

The reason for this is because the E7 features a G# note, the Major 7th in the key of A minor. Our A minor pentatonic and A natural minor scales by contrast feature a b7th interval, or G natural.

The building blocks of puzzles are instead music notes ranging, quite literally, across the scale. As you play the notes are combined into melodies and ranges that create magical effects.