gilsp( https://github.com/baku89/glisp )用スクリプトです

sketch_dec-03-2020_21-03-24.glisp,shspage.glisp

(def spiral_radius 30)
(def interval 1.2)
(def arc_angle (deg 80))

(defn prepare [tr t r]
	(if (> r spiral_radius)
		tr
  	(let [t1 (+ t (atan2 interval r))
  	      r1 (+ r (/ interval t1))]
	    (prepare (conj tr t1 r1) t1 r1))))

(defn uzu
	[fill_col circle_size scale_val]
	(let [trs (prepare [] 0 0)]
	  (style (fill fill_col)
		(transform
			(scale [scale_val scale_val])
			(for [n (range 0 (count trs) 2)]
			  (let [t (nth trs n)
			        r (nth trs (inc n))]
			     (arc [(* r (cos t))
			           (* r (sin t))]
			           circle_size
			           t (+ t arc_angle))
			))))))
		
:start-sketch

(background "#fff")

(uzu "#eee" 3 10.2)
(uzu "#aaa" 2.5 10.1)
(uzu "#000" 2 10)