xtree.scm

(define decorate #f)
(let ((pos-seed 1)
      (shape-seed 1))
  (set! decorate
    (lambda (leaves)
      (for-each 
        (lambda (_) 
          (set! pos-seed (modulo (+ (* pos-seed 3) 7) 26))
          (set! shape-seed (modulo (+ shape-seed 1) 3))
          (if (< pos-seed (string-length leaves))
            (string-set! leaves pos-seed
                         (list-ref '(#\@ #\? #\$) shape-seed)))) 
        (make-list 3))
      leaves)))


(define tree-data 
    (let loop1 ((width '( 0 2 6 10 ))(updates '(1 1 2 2 ) ))
      (if (null? width) 
        '()
        (append 
          (let loop2 ((w (min 1 (car width))))
            (if (> w (car width))
              '()
              (cons 
                (string-append
                  (substring "                             " 0 (- 13 w))
                  (decorate (substring "*****************************" 0 (+ (* w 2) 1))))
                (loop2 (+ w (car updates) )))))
          (loop1 (cdr width)(cdr updates))))))

(define tree-pot
  (let ((space "          ")
        (edge  "|     |")
        (bottom "-------"))
    (append
      (map (lambda (_)
             (string-append space edge))
           (make-list 2 ))
      (list (string-append space bottom)))))


(for-each 
  (lambda (x) (display x)(newline))
  (append tree-data tree-pot))