dominant, freestanding sculpture was done as well. Freestanding three-dimensional stone sculpture began with the Olmecs, with the most famous example being the giant Olmec stone heads. This disappeared for the rest of the Mesoamerican period in favor of relief work until the late post-Classic with the Aztecs. The majority of stonework during the Mesoamerican period is associated with monumental architecture that, along with mural painting, was considered an integral part of architecture rather than separate. Monumental architecture began with the Olmecs in southern Veracruz and the coastal area of Tabasco in places such as San Lorenzo; large temples on pyramid bases can still be seen in sites such as Montenegro, Chiapa de Corzo and La Venta. This practice spread to the Oaxaca area and the Valley of Mexico, appearing in cities such as Monte Albán, Cuicuilco and Teotihuacan. These cities had a nucleus of one or more plazas, with temples, palaces and Mesoamerican ball courts. Alignment of these structures was based on the cardinal directions and astronomy for ceremonial purposes, such as focusing the sun's rays during the spring equinox on a sculpted or painted image. This was generally tied to calendar systems. Relief sculpture and/or painting were created as the structures were built. By the latter pre-Classic, almost all monumental structures in Mesoamerica had extensive relief work. Some of the best examples of this are Monte Albán, Teotihuacan and Tula. Pre-Hispanic reliefs are general lineal in design and low, medium and high reliefs can be found. While this technique is often favored for narrative scenes elsewhere in the world, Mesoamerican reliefs tend to focus on a single figure. The only time reliefs are used in the narrative sense is when several relief steles are placed together. The best relief work is from the Mayas, especially from Yaxchilan. Writing and art were not distinct as they have been for European cultures. Writing was considered art and art was often covering in writing. The reason for this is that both sought to record history and the culture's interpretation of reality. (salvatvolp14) Manuscripts were written on paper or other book-like materials then bundled into codices. The art of reading and writing was strictly designated to the highest priest classes, as this ability was a source of their power over society. The pictograms or glyphs of this writing system were more formal and rigid than images found on murals and other art forms