Game of Life in Clojure, slightly modified from original here: http://clj-me.cgrand.net/2011/08/19/conways-game-of-life/

gol.clj

(ns joyful-game.game-of-life)
 
(defn neighs [[x y]] 
    (for [dx [-1 0 1] 
          dy [-1 0 1]
          :when (not (= 0 dy dx))] 
        [(+ x dx) (+ y dy)]))
 
(defn should-be-alive [nc is-alive]
    (or (= nc 3)
        (and (= nc 2) is-alive)))
 
(defn step [board]
    (->> board
         (mapcat neighs)
         frequencies
         (filter (fn [[cell frq]] (should-be-alive frq (board cell))))
         (map first)
         set))