The world is shapes and colors.  I used to teach a lesson about  synesthesia.  I found an article in U.S. News and World Report years ago on the phenomenon of synesthesia.  It's rare, but in some individuals, when they experience one sense, another comes into play.  Many artists and musicians have it.  For example, when a young man heard a car go by he saw dots.  When a girl kissed her boyfriend she saw orange sherbet foam.  When a woman heard her husband's voice, she tasted warm buttery toast.  According to the researcher in the article, all the secondary senses involved in the experience are primitive.  W. Kandinsky paints to sounds.  The colors and images come from the sound.

My first car was a 1978 Mercury Cougar, a gas guzzling beast.  I loved that car.  When my son was little and the muffler fell off, he used to say "go fast Mommy" so he could hear the roar.  I'll bet a synesthete would have gone nuts if s/he had heard that monster flying by.  Gray, red, purple, black dots -- the speed of sound.  What a light show