(low low+1 low+2 ... high-1 high)
Q: What list of this form is such that low > high?
A: The empty list
| Q: | If you have the number | low |
| and the list | (low+1 low+2 ... high), | |
| how do you create | (low low+1 low+2 ... high)? |
A: cons low onto (low+1 low+2 ... high-1 high)