gistfile1.clj

(defn- splits [loc]
  (let [node (z/node loc)]
    (when (set? node)
      (map #(z/replace loc %) node))))

(defn zip-product [z]
  (if-let [next-split-loc
           (->> z
             (iterate z/next)
             (take-while (complement z/end?))
             (drop-while (complement splits))
             first)]
    (mapcat zip-product
            (splits next-split-loc))
    [z]))

(->> [[[#{1 2 3} #{4 5 6}] #{7 8 9}]]
  z/vector-zip
  zip-product
  (map z/root))

;; ([[[1 4] 7]]
;;  [[[1 4] 8]]
;;  [[[1 4] 9]]
;;  [[[1 5] 7]]
;;  [[[1 5] 8]]
;;  [[[1 5] 9]]
;;  [[[1 6] 7]]
;;  [[[1 6] 8]]
;;  [[[1 6] 9]]
;;  [[[2 4] 7]]
;;  [[[2 4] 8]]
;;  [[[2 4] 9]]
;;  [[[2 5] 7]]
;;  [[[2 5] 8]]
;;  [[[2 5] 9]]
;;  [[[2 6] 7]]
;;  [[[2 6] 8]]
;;  [[[2 6] 9]]
;;  [[[3 4] 7]]
;;  [[[3 4] 8]]
;;  [[[3 4] 9]]
;;  [[[3 5] 7]]
;;  [[[3 5] 8]]
;;  [[[3 5] 9]]
;;  [[[3 6] 7]]
;;  [[[3 6] 8]]
;;  [[[3 6] 9]])