ROY "Tractor" BIV

As everyone knows that BB likes cars, he receives a lot as presents. He has two tractors, one which is an official "John Deere" tractor, and the other which is a look-alike. BB has learned the word tractor, and since both of his tractors are green, BB thinks that anything that is green is a tractor. I can just see it now when BB is asked what colors are in the rainbow: "red, orange, yellow, tractor, blue, indigo, violet."