if self.thing.world.map_[test_pos] != '.':
raise GameError('%s would move into illegal terrain' % self.thing.id_)
for t in self.thing.world.things:
if self.thing.world.map_[test_pos] != '.':
raise GameError('%s would move into illegal terrain' % self.thing.id_)
for t in self.thing.world.things: