(define (mandel)
  (do ((y -1.4 (+ y 0.1))) ((> y 1.5))
    (do ((x -2 (+ x 0.04))) ((> x 1))
      (let ((a (make-rectangular x y)))
        (let loop ((z a) (c 126))
          (let ((q (+ a (* z z))))
            (if (and (< (magnitude q) 2) (> c 32))
                (loop q (- c 1))
                (display (integer->char c)))))))
    (newline)))

(mandel)