Because of a unique production process that uses what are called “tranchet blows,” Tiya tools might also belong to the same time span as these other two sites. Other points of interest near Tiya include Melka Awash, the Hera Shetan crater lake, and Agesoke, a place where very tall, naturally ordered stone blocks can be seen. According to Joussaume (1995), who led archaeological work at Tiya, the site is relatively recent. It was dated to a time period between the 11th and 13th centuries CE. Later dating places the stelae's construction some time between the 10th and 15th centuries CE. However, the building of megaliths in Ethiopia is a very ancient tradition, with many such monuments predating the Common Era. Tiya is one of nine megalithic pillar sites in the Gurage Zone. As of 1997, 118 stelae were reported in the area. Along with the stelae in the Hadiya Zone, the structures are identified by local residents as "Yegragn Dingay" or "Gran's stone", in reference to Imam Ahmad ibn Ibrahim al-Ghazi (Ahmad "Gurey" or "Gran"), ruler of the Adal Sultanate. The Gurage stelae are of three types: anthropomorphic stelae with human figures, phallic stelae, and stelae of neither anthropomorphic nor phallic type. The anthropomorphic and non-anthropomorphic/non-phallic stelae types are flat in shape, being the only stelae of this form in the southern region. Most of these stelae, including the 46 ones at Tiya, which are the largest of the bunch, also have distinctive, elaborate decorations. Among these designs are swords, plant-like symbols, and a standing human figure with arms akimbo. The plant and sword emblems can be found on the same stelae. The sword design is reportedly of local "Galla" type, as made by the Oromo. The shape of its blade is likewise the same as that of a traditional Somali dagger. In addition, the Tiya rock slabs also often feature a T-shaped symbol. The stelae at Tiya and other areas in central Ethiopia are similar to those on the route between Djibouti City and Loyada in Djibouti. In the latter area, there are a number of anthropomorphic and phallic stelae, which are associated with graves of rectangular shape flanked by vertical slabs.