char *graphics_set; /* optional custom graphics set (level tree only) */
char *sounds_set; /* optional custom sounds set (level tree only) */
char *music_set; /* optional custom music set (level tree only) */
char *graphics_set; /* optional custom graphics set (level tree only) */
char *sounds_set; /* optional custom sounds set (level tree only) */
char *music_set; /* optional custom music set (level tree only) */