+ def __getitem__(self, yx):
+ return self.terrain[self.get_position_index(yx)]
+
+ def __setitem__(self, yx, c):
+ pos_i = self.get_position_index(yx)
+ if type(c) == str:
+ self.terrain = self.terrain[:pos_i] + c + self.terrain[pos_i + 1:]
+ else:
+ self.terrain[pos_i] = c
+
+ def __iter__(self):
+ """Iterate over YX position coordinates."""
+ for y in range(self.size[0]):
+ for x in range(self.size[1]):
+ yield (y, x)
+