Time Across, Pitch Up

Written music is a graph, and once somebody says so there is almost nothing left to memorize. How far across a note sits is when it happens; how far up it sits is how high it sounds. Five lines and four gaps make nine places, the letters run A to G and then start again because the eighth note sounds like the first, and the clef is the thing that says which line is which. It ends on three numbers that refuse to fit each other — five lines, seven names, twelve notes — which is where the black keys came from and what next year is about.