+uint16_t read_uint16_bigendian(FILE * file);
+void write_uint16_bigendian(uint16_t x, FILE * file);
+uint32_t read_uint32_bigendian(FILE * file);
+void write_uint32_bigendian(uint32_t x, FILE * file);
+void load_game(struct World *);
+void save_game(struct World *);