I play drums so when I have a song in my head I often walk to the rhythm. However my left foot has to go with the snare beat and when I'm walking on the street, my left foot has to go on a lighter bit of the path, preferably white, whereas my right foot goes with the first hi hat beat and has to go on a dark, preferably black, part of the pavement. Thus when I can't find the right shades of colour on the pavement, I pause the song in my head and wait till I can find the right shade of tone.
I'm not even sure I should admit that.