When I first started taking piano lessons, I memorized my pieces by remembering the "color" of each note and chord. Fast forward...about fifteen years later. I was working with a piano student who had a hard time playing Chopin's Prelude in E Minor. He had to memorize it for a piano audition, and he kept messing up the chords. I remember saying to him "Hit the green chord! Hit the yellow chord!". He looked very confused, but he was too shy to say anything. Fast forward..