Rainbow
Red Yellow Blue Purple
#FF0000 #FFFF00 #0000FF #FF00FF
rgb(255,0,0) rgb(255,255,0) rgb(0,0,255) rgb(255,0,255)
hsl(0%,100%,50%) hsl(60%,100%,50%) hsl(240%,100%,50%) hsl(300%,100%,50%)