T9872a.hs:17:8: error:
    • No instance for ‘Show
                         (Proxy
                            (Cons
                               (Cons
                                  (Cube G B W R B G)
                                  (Cons
                                     (Cube W G B W R R)
                                     (Cons (Cube R W R B G R) (Cons (Cube B R G G W W) Nil))))
                               (Cons
                                  (Cons
                                     (Cube G B R W B G)
                                     (Cons
                                        (Cube R R W B G W)
                                        (Cons (Cube R G B R W R) (Cons (Cube W W G G R B) Nil))))
                                  (Cons
                                     (Cons
                                        (Cube G W R B B G)
                                        (Cons
                                           (Cube W B W R G R)
                                           (Cons (Cube R R B G W R) (Cons (Cube B G G W R W) Nil))))
                                     (Cons
                                        (Cons
                                           (Cube G R W B B G)
                                           (Cons
                                              (Cube R W B G R W)
                                              (Cons
                                                 (Cube R B R W G R) (Cons (Cube W G G R W B) Nil))))
                                        (Cons
                                           (Cons
                                              (Cube G R B B W G)
                                              (Cons
                                                 (Cube W W R G B R)
                                                 (Cons
                                                    (Cube R B G W R R)
                                                    (Cons (Cube B G W R G W) Nil))))
                                           (Cons
                                              (Cons
                                                 (Cube G W B B R G)
                                                 (Cons
                                                    (Cube R B G R W W)
                                                    (Cons
                                                       (Cube R R W G B R)
                                                       (Cons (Cube W G R W G B) Nil))))
                                              (Cons
                                                 (Cons
                                                    (Cube G B B W R G)
                                                    (Cons
                                                       (Cube W R G B W R)
                                                       (Cons
                                                          (Cube R G W R B R)
                                                          (Cons (Cube B W R G G W) Nil))))
                                                 (Cons
                                                    (Cons
                                                       (Cube G B B R W G)
                                                       (Cons
                                                          (Cube R G R W B W)
                                                          (Cons
                                                             (Cube R W G B R R)
                                                             (Cons (Cube W R W G G B) Nil))))
                                                    Nil)))))))))’
        arising from a use of ‘print’
    • In the expression: print (Proxy :: Proxy (Solutions Cubes))
      In an equation for ‘main’:
          main = print (Proxy :: Proxy (Solutions Cubes))