(def dihedral-subtract
     (# (a b order)
        (let (u_1 (>> a 1)
              v_1 (& a 1)
              u_2 (>> b 1)
              v_2 (& b 1))
          (if (= 1 v_1)
              (bit-or (<< (% (+ order u_1 (- u_2)) (>> order 1)) 1)
                      (if (zero? v_2) 1 0))
            (bit-or (<< (% (+ u_1 u_2) (>> order 1)) 1)
                      v_2)))))

(def get-order (let (n (integer (nth process.argv 2)))
                (cond
                 ((or (not (integer? n)) (< n 1)) 6)
                 ((odd? n) (--1 n))
                 (true n))))

(process.stdout.write "   ")
(times (i get-order)
       (process.stdout.write (cat i " ")))
(process.stdout.write "\n")
(times (i get-order)
       (process.stdout.write (cat i "  "))
       (times (j get-order)
              (process.stdout.write (cat (dihedral-subtract i j get-order) " ")))
       (process.stdout.write "\n"))