UTF-8 Mandelbrot in Clojure

mandel.clj

(def screen-width 100)
(def screen-height 30)

(defn scaled-x [x]
  (- (* (/ x screen-width) 3.5) 2.5))

(defn scaled-y [y]
  (- (* (/ y screen-height) 2) 1))

(defn mandel [x y iteration x0 y0 max-iteration]
  (if (and
        (< (+ (* x x) (* y y)) 4)
        (< iteration max-iteration))
    (let [x' (+ (- (* x x) (* y y)) x0)
          y' (+ (* 2 x y) y0)]
      (recur x' y' (inc iteration) x0 y0 max-iteration))
    iteration))

(defn char-for-c [c]
  (nth " ░▒▓█" (/ c 8) "█"))

(defn draw-pixel [pixel-x pixel-y]
  (let [x0 (scaled-x pixel-x)
        y0 (scaled-y pixel-y)
        c (mandel 0 0 0 x0 y0 1000)]
    (print (char-for-c c))))

(defn draw-fractal []
  (dotimes [y screen-height]
    (dotimes [x screen-width]
      (draw-pixel x y))
    (println)))

(draw-fractal)

Wow. Very impressed. :-D