Heller's made good use of color symbolism [as we all know by now] since the characters seem to be affiliated to a color

And the rainbow, of course, is also known as ROYGBIV  [I had to chuckle that the rainbow starts with ROY LOL]

Red, Orange, Yellow, Green, Blue, Indigo, Violet/White

Likewise, the Chakra system is modeled after roygbiv, with each color related to an area in the body [though this varies somewhat].  Red starts at the base of the spine and goes to above the top of the head [Violet/White]