Some context: Fazlur Rahman Khan (Bengali: phjlur rhmaan khaan, Fozlur Rohman Khan) (3 April 1929 - 27 March 1982) was a Bangladeshi-American structural engineer and architect, who initiated important structural systems for skyscrapers. Considered the "father of tubular designs" for high-rises, Khan was also a pioneer in computer-aided design (CAD). He was the designer of the Sears Tower, since renamed Willis Tower, the tallest building in the world from 1973 until 1998, and the 100-story John Hancock Center. Khan, more than any other individual, ushered in a renaissance in skyscraper construction during the second half of the 20th century.
Khan's central innovation in skyscraper design and construction was the idea of the "tube" structural system for tall buildings, including the framed tube, trussed tube, and bundled tube variants. His "tube concept", using all the exterior wall perimeter structure of a building to simulate a thin-walled tube, revolutionized tall building design. Most buildings over 40 stories constructed since the 1960s now use a tube design derived from Khan's structural engineering principles.  Lateral loads (horizontal forces) such as wind forces, seismic forces, etc., begin to dominate the structural system and take on increasing importance in the overall building system as the building height increases. Wind forces become very substantial, and forces caused by earthquakes, etc. are important as well. The tubular designs resist such forces for tall buildings. Tube structures are stiff and have significant advantages over other framing systems. They not only make the buildings structurally stronger and more efficient, but also significantly reduce the structural material requirements. The reduction of material makes the buildings economically more efficient and reduces environmental impact. The tubular designs enable buildings to reach even greater heights. Tubular systems allow greater interior space and further enable buildings to take on various shapes, offering added freedom to architects. These new designs opened an economic door for contractors, engineers, architects, and investors, providing vast amounts of real estate space on minimal plots of land. Khan was among a group of engineers who encouraged a rebirth in skyscraper construction after a hiatus of over thirty years.  The tubular systems have yet to reach their limit when it comes to height. Another important feature of the tubular systems is that buildings can be constructed using steel or reinforced concrete, or a composite of the two, to reach greater heights. Khan pioneered the use of lightweight concrete for high-rise buildings, at a time when reinforced concrete was used for mostly low-rise construction of only a few stories in height. Most of Khan's designs were conceived considering pre-fabrication and repetition of components so projects could be quickly built with minimal errors.  The population explosion, starting with the baby boom of the 1950s, created widespread concern about the amount of available living space, which Khan solved by building upward. More than any other 20th-century engineer, Fazlur Rahman Khan made it possible for people to live and work in "cities in the sky." Mark Sarkisian (Director of Structural and Seismic Engineering at Skidmore, Owings & Merrill) said, "Khan was a visionary who transformed skyscrapers into sky cities while staying firmly grounded in the fundamentals of engineering."
What other materials does this system use?
A: Khan pioneered the use of lightweight concrete for high-rise buildings,
Some context: The Maya civilization was a Mesoamerican civilization developed by the Maya peoples, and noted for its hieroglyphic script--the only known fully developed writing system of the pre-Columbian Americas--as well as for its art, architecture, mathematics, calendar, and astronomical system. The Maya civilization developed in an area that encompasses southeastern Mexico, all of Guatemala and Belize, and the western portions of Honduras and El Salvador. This region consists of the northern lowlands encompassing the Yucatan Peninsula, and the highlands of the Sierra Madre, running from the Mexican state of Chiapas, across southern Guatemala and onwards into El Salvador, and the southern lowlands of the Pacific littoral plain. The Archaic period, prior to 2000 BC, saw the first developments in agriculture and the earliest villages.
The Maya developed their first civilization in the Preclassic period. Scholars continue to discuss when this era of Maya civilization began. Maya occupation at Cuello (modern-day Belize) has been carbon dated to around 2600 BC. Settlements were established around 1800 BC in the Soconusco region of the Pacific coast, and the Maya were already cultivating the staple crops of maize, beans, squash, and chili pepper. This period was characterized by sedentary communities and the introduction of pottery and fired clay figurines.  During the Middle Preclassic Period, small villages began to grow to form cities. Nakbe in the Peten department of Guatemala is the earliest well-documented city in the Maya lowlands, where large structures have been dated to around 750 BC. The northern lowlands of Yucatan were widely settled by the Middle Preclassic. By approximately 400 BC, early Maya rulers were raising stelae. A developed script was already being used in Peten by the 3rd century BC. In the Late Preclassic Period, the enormous city of El Mirador grew to cover approximately 16 square kilometres (6.2 sq mi). Although not as large, Tikal was already a significant city by around 350 BC.  In the highlands, Kaminaljuyu emerged as a principal centre in the Late Preclassic. Takalik Abaj and Chocola were two of the most important cities on the Pacific coastal plain, and Komchen grew to become an important site in northern Yucatan. The Late Preclassic cultural florescence collapsed in the 1st century AD and many of the great Maya cities of the epoch were abandoned; the cause of this collapse is unknown.
Anything interesting in 2000BC or near that time?
A:
The Maya developed their first civilization in the Preclassic period. Scholars continue to discuss when this era of