Game of Life in Clojure (modified from http://clj-me.cgrand.net/2011/08/19/conways-game-of-life/)

gol

(ns gol)

(defn grid-with-center [[x y]]
  (let [deltas [-1 0 1]]
    (for [delta-x deltas delta-y deltas]
      [(+ x delta-x) (+ y delta-y)])))

(defn center? [center]
  (partial = center))

(defn neighbours [cell]
  (remove (center? cell) (grid-with-center cell)))

(defn all-neighbours-of [cells]
  (mapcat neighbours cells))

(defn will-live? [cell quantity lives?]
  (or
    (= quantity 3)
    (and (= quantity 2)
         (lives? cell))))

(defn step [living-cells]
  (set
    (for [[cell quantity] (frequencies (all-neighbours-of living-cells))
          :when (will-live? cell quantity living-cells)]
      cell)))

(def living-cells #{[1 0] [1 1] [1 2]})

(take 5 (iterate step living-cells))