Starting with the Citadel-86 code, Matt duplicated all of Stonehenge's features, plus he also added many of his own. This code served as the root for almost all subsequent Citadel development in the Seattle area. He stopped work on it after 1.30 (which was never used), only to return several years later, starting with Dragon's Citadel code. This resulted in Gremlin's Citadel and Citadel+.