scratch.clj

(defn inside? [[z-re z-im]]
  (> (+ (* z-re z-re) (* z-im z-im)) 4))

(defn step [c-re c-im [z-re z-im]]
  [(+ (* 2 z-re z-im) c-im)
   (+ (- (* z-re z-re) (* z-im z-im)) c-re)])

(doseq [y (range image-height)
        :let [c-im (- max-im (y * im-factor))]
        x (range image-width)]
  (let [c-re (+ min-re (x * re-factor))]
   (when (some inside?
               (take max-iterations
                     (iterate #(step c-re c-im %)  [c-re c-im])))
     (put-pixel x y))))