Inspired by this: http://koku-chou.tumblr.com/post/69509732291/circles

pixercles.clj

(ns pixercles
  (:use quil.core))

(def screen-w 2000)
(def screen-h 1000)

(defn- rand-color []
  (vec (repeatedly 3 (fn [] (rand-int 255)))))

(defn- vary-color [c]
  (let [delta-c (vec (repeatedly 3 (fn [] (- (rand-int 40) 20))))]
    (map + c delta-c)))

(defn- generate-palette [n]
  (vec (repeatedly n (fn [] (rand-color)))))

(defn- cell [radius palette opacity]
  (let [seed-color (palette (rand-int (count palette)))
        desired-color (vary-color seed-color)]
    (apply fill (conj desired-color opacity))
    (ellipse 0 0 radius radius)))

(defn setup []
  (smooth)
  (no-loop))

(defn draw []
  (let [bg-color [0 0 0]
        radius 75
        circle-distance (* radius 0.7)
        columns (inc (/ screen-w circle-distance))
        rows (inc (/ screen-h circle-distance))
        circle-color [255 255 255]
        circle-thickness 2
        palette (generate-palette 5)
        opacity 150]
    (apply background bg-color)
    (ellipse-mode :center)
    (stroke-weight circle-thickness)
    (apply stroke circle-color)

    (doseq [y (range rows)]
      (push-matrix)
      (doseq [x (range columns)]
        (cell radius palette opacity)
        (translate circle-distance 0)
        )
      (pop-matrix)
      (translate 0 circle-distance)
      )
    )
    (display-filter :blur 1)
    (save "pixercles.png")
  )

(defsketch main
  :title "pixercles"
  :setup setup
  :draw draw
  :size [screen-w screen-h]
  :renderer :java2d
  )