AdjustDescendantMass() calls NotifyParentOfMassChange and updates local cache AdjustSelfMass() calls NotifyParentOfMassChange and updates local value NotifyParentOfMassChange() calls AdjustDescendantMass of ancestor SetParent() calls NotifyParentOfMassChange Dynasties have lists of memos. Memos can contain news cuttings. Memos are from people. News cuttings can mention people. People have locations.