list<Building> internal_build_skyline (list<Building> *) const;
Real internal_distance (Skyline const &, Real horizon_padding, Real *touch_point) const;
Real internal_distance (Skyline const &, Real *touch_point) const;
void normalize ();
list<Building> internal_build_skyline (list<Building> *) const;
Real internal_distance (Skyline const &, Real horizon_padding, Real *touch_point) const;
Real internal_distance (Skyline const &, Real *touch_point) const;
void normalize ();