def get_domain(self):
        """
        :returns: opposite vertices of the bounding prism for this 
            object in the form of ndarray([min], [max])
        
        .. note:: This method automatically stores the solution in order
            to do not repeat calculations if the user needs to call it 
            more than once.
        """
        points = ([poly.points for poly in self]+
                  [holes.points for holes in self.holes])
        points = np.concatenate(points, axis=0)
        return np.array([points.min(axis=0), points.max(axis=0)])