enum COLOUR         { C_WHITE, C_BLACK };
enum STONE_VARIANT  { STONE_FLAT, STONE_STANDING, STONE_CAPSTONE };
enum MOVE_DIRECTION { M_UP, M_DOWN, M_LEFT, M_RIGHT };
enum ACTION_RESULT  { A_OK, A_ILLEGAL, A_OVERFLOW };
enum WIN_RESULT     { W_NONE, W_ROAD_WHITE, W_ROAD_BLACK, W_FLAT_WHITE, W_FLAT_BLACK };