ForwardTracker::Spacer Node1 ForwardTracker::Spacer - m_label - m_side - m_frontFace - m_rearFace - m_position + Spacer() + Spacer() + ~Spacer() + clone() + label() + side() + frontFace() + rearFace() + position() + isEndElement() + track() + str() Node2 ForwardTracker::IBeamElement + ~IBeamElement() + label() + side() + frontFace() + rearFace() + position() + isEndElement() + track() + clone() + str() Node2->Node1