test.clj

(defn move-hex
  [point direction]
    (case direction
      :ne [(inc (point 0)) (dec (point 1))]
      :se [(inc (point 0)) (point 1)]
      :s  [(point 0) (inc (point 1))]
      :sw [(dec (point 0)) (inc (point 1))]
      :nw [(dec (point 0)) (point 1)]
      :n  [(point 0) (dec (point 1))]))

(defn traverse-grid-from-origin
  [directions]
  (loop [point [0 0]
         max-distance 0
         directions directions]
  (cond
    (empty? directions) (max-distance point)
    :else (let [new-point (move-hex point (first directions))
                current-distance (max-distance new-point)]
            (recur new-point
                   (if (>= current-distance max-distance)
                     current-distance
                     max-distance)
                   (rest directions))))))


(defn max-distance
  [point]
  (Math/max (Math/abs (point 0)) (Math/abs (point 1))))

;; this fails when running, but stepping through it works.
(traverse-grid-from-origin [:s])