(defn hyp [x y r]
  (Math/sqrt (+ (Math/pow (Math/abs (- r x)) 2)
                (Math/pow (Math/abs (- r y)) 2))))

(defn dist [x y r] (Math/abs (- (hyp x y r) r)))

(defn circle [r]
  (let [rep (for [x (range (inc (* r 2))) y (range (inc (* r 4)))]
              {:x x :y y :val \ })
        circle? (fn [c] (let [d (dist (:x c) (double (/ (:y c) 2)) r)]
                          (cond (<= d 0.25) \#
                                (<= d 0.75) \=
                                (<= d 1.5) \-
                                :else \ )))]
    (map circle? rep)))

(defn group [r c]
  (let [tail (drop r c)]
    (if (empty? tail)
      [c]
      (lazy-cat [(take r c)] (group r tail)))))

(defn get-rows [c] (map #(apply str %) c))

(defn echo-circle [c] (doall (map prn c)))

(defn simple-circle [r] (get-rows (group (inc (* r 4)) (circle r))))

; IDEA:
; Given radius r,
;   iterate over 0 - r * 2 rows
;   Decide for 0 - r * 4 columns
; (Can be done in parallel ie multi-dim seq of agents)
; Just str the seq

(echo-circle (simple-circle 10))