Along with their calendars -- the Tzolk'in, the Haab and the Long Count -- the Mayans also created their own math system. They used a series of dots and bars to signify numbers. One dot equaled one unit, while one bar equaled five units. A shell symbol signified zero.
Nullarbor is bounded in the west by the Western Australia-South Australian state border, in the south by the coastline adjoining the Great Australian Bight, to the east by the localities of Yalata and Yellabinna and to the north by the Trans-Australian Railway.ullarbor is located within the federal Division of Grey, the state electoral districts of Flinders and Giles, and the unincorporated area of South Australia.
Space Shuttle photo STS049-097-054 taken in May 1992 and looking northeast across Tambora. Tambora is a stratovolcano, forming the Sanggar peninsula of Sumbawa Island. The diameter of the volcano at sea-level is about 38 miles (60 km). Prior to the 1815 eruption, the volcano may have been as tall as 13,000 feet (4,000 m). The 1815 eruption formed a caldera about 4 miles (6 km) in diameter.