More progress on the Shut the Box program in Racket.

Still need to figure out how to get everything together, but at least it's starting to make some sense.

```
#lang racket
#| Init Block |#
(define tiles '())
(define die1 0)
(define die2 0)
(define turn-number 1)
(define (start-game)
(set! tiles '(1 2 3 4 5 6 7 8 9)))
(define (dice)
(+ 1 (random 6)))
(define (dice-roll)
(set! die1 (dice))
(set! die2 (dice)))
(define (sum-of-dice)
(+ die1 die2))
(define (sum-of-tiles tilelist)
(apply + tilelist))
(define (check-roll dice-sum tile-sum)
(= dice-sum tile-sum))
(define (shut-tiles tilelist)
(for ([i tilelist])
(if (index-of tiles i)
(set! tiles (remove i tiles))
(print "Tile already shut"))))
(define (player-turn tilelist)
(if (check-roll (sum-of-dice) (sum-of-tiles tilelist))
(shut-tiles tilelist)
(print "Roll does not equal shut tiles. Try again.")))
(start-game)
(dice-roll)
(define (next-turn)
(set! turn-number (+ 1 turn-number))
(dice-roll)
(show-turn))
(define (show-turn)
(printf "Turn: ")
(println turn-number)
(println tiles)
(printf "Dice roll ~v ~v = ~v" die1 die2 (sum-of-dice) ))
```