(define (tengrand n)
  (> n 0)
  (<= n 100))
(define (zero n)
  (> n 100)
  (<= n 200))
(define (negative n)
  (< n 0))
(define (truezero n)
  (= n 0))
(define (squarewave n)
  (cond [(truezero n) 0]
        [(negative n) (squarewave (+ (- 0 n) 100))]
        [(tengrand n) 10000]
        [(zero n) 0]
        [else (squarewave (- n 200))]))