i believe that you can never see the end of the rainbow as it changes when you move
"Do two people ever see the same rainbow?" Humphreys points out that "since the rainbow is a special distribution of colors (produced in a particular way) with reference to a definite point - the eye of the observer - and as no single distribution can be the same for two separate points, it follows that two observers do not, and cannot, see the same rainbow." In fact, each eye sees its own rainbow!!