+extern const unsigned int empty; /* 0 */
+extern const unsigned int white; /* 1 */
+extern const unsigned int black; /* 2 */
+
+extern const unsigned int player_one; /* black */
+extern const unsigned int player_two; /* white */
+
+
+extern const unsigned int hint_allowed; /* legal place for a pawn */
+extern const unsigned int hint_forbidden; /* illegal place for a pawn */