Sierpinski Gasket code

gistfile1.sls

(defn sierpinskisize
  "Chooses a vertex from tri at random, returning the point halfway between
p and the vertex."
  [p tri]
  (let [v-num (rand-int 3)
        vertex ((case v-num
                      0 :p1
                      1 :p2
                      2 :p3) tri)
        halfway-point (fn [p1 p2]
                        (for [coord [:x :y :z]]
                          (/ (+ (coord pi) (coord p2)) 2)))]
    (apply make-point (halfway-point vertex p))))