Answer the question at the end by quoting:

George Washington (February 22, 1732 - December 14, 1799) was an American statesman and soldier who served as the first President of the United States from 1789 to 1797 and was one of the Founding Fathers of the United States. He served as Commander-in-Chief of the Continental Army during the American Revolutionary War, and later presided over the 1787 convention that drafted the United States Constitution. As a driving force behind the nation's establishment he came to be known as the "father of the country," both during his lifetime and to this day. Washington was born into the provincial gentry of Colonial Virginia to a family of wealthy planters who owned tobacco plantations and slaves, which he inherited.
George Washington was the first child of Augustine Washington and his second wife Mary Ball Washington, born on their Popes Creek Estate near Colonial Beach in Westmoreland County, Virginia. He was born on February 11, 1731, according to the Julian calendar and Annunciation Style of enumerating years then in use in the British Empire. The Gregorian calendar was adopted within the British Empire in 1752, and it renders a birth date of February 22, 1732.  Washington was of primarily English gentry descent, especially from Sulgrave, England. His great-grandfather John Washington immigrated to Virginia in 1656 and began accumulating land and slaves, as did his son Lawrence and his grandson, George's father Augustine. Augustine was a tobacco planter who also tried his hand at iron manufacturing, and later he was the Justice of the Westmoreland County Court. In Washington's youth, his family was moderately prosperous and considered members of Virginia's "country level gentry" of "middling rank," rather than one of the leading wealthy planter elite families. His wife Sally was also a friend of Washington and an early romantic interest, and maintained correspondence when she moved to England with her father, but most of the letters were intercepted by the British during the war.  Lawrence Washington inherited a plantation from their father on the Potomac River at Little Hunting Creek which he named Mount Vernon in honor of his commanding officer Vice Admiral Edward Vernon. Washington inherited Ferry Farm upon his father's death and eventually acquired Mount Vernon after Lawrence's death.  The death of his father prevented Washington from an education at England's Appleby Grammar School such as his older brothers had received. He achieved the equivalent of an elementary school education from a variety of tutors, as well as from a school run by an Anglican clergyman in or near Fredericksburg. His education totaled seven or eight years, while he lived with relatives at various places that included the Westmoreland and the Chotank regions of Virginia, as well as Ferry Farm and Mount Vernon. He was trained in mathematics, trigonometry, and surveying that developed a natural talent of draftsmanship and map making. He was also an avid reader and purchased books on military affairs, agriculture, and history, as well as the popular novels of his times. There was talk of securing an appointment for him in the Royal Navy when he was 15, but it was dropped when his widowed mother objected.  In 1751, Washington traveled with Lawrence to Barbados (his only trip abroad) in the hope that the climate would be beneficial to Lawrence's declining health, as he was suffering from tuberculosis. Washington contracted smallpox during the trip, which left his face slightly scarred but immunized him against future exposures to the disease. Lawrence's health failed to improve, and he returned to Mount Vernon where he died in the summer of 1752. His position as Adjutant General (militia leader) of Virginia was divided into four district offices after his death, and Washington was appointed by Governor Dinwiddie as one of the four district adjutants in February 1753, with the rank of major in the Virginia militia. He also became a freemason while in Fredericksburg during this period, although his involvement was minimal.

When was he born?

February 11, 1731,



Answer the question at the end by quoting:

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."

Is there any popular buildings that use this structural design?
Khan was a visionary who transformed skyscrapers into sky cities