The Japanese architect had previously built the Saudi Arabian black rock complex and was hired by the bin Laden's to do it. The he built the twin towers. The twin towers feature the standard two towers around a rock like object on the ground which was the world sphere. The bottom arches on the twin towers were Arabic pointed arches. Since the bin Laden's were involved with the architect they would have at least had the plans. I find it interesting that in Yamasaki Wikipedia page his work on the Saudi buildings has been expunged from his list of projects but here is an article about it. https://slate.com/culture/2001/12/bin-laden-s-special-complaint-with-the-world-trade-center.html https://archive.is/PgFrR >Yamasaki received the World Trade Center commission the year after the Dhahran Airport was completed. Yamasaki described its plaza as “a mecca, a great relief from the narrow streets and sidewalks of the surrounding Wall Street area.” True to his word, Yamasaki replicated the plan of Mecca’s courtyard by creating a vast delineated square, isolated from the city’s bustle by low colonnaded structures and capped by two enormous, perfectly square towers—minarets, really. Yamasaki’s courtyard mimicked Mecca’s assemblage of holy sites—the Qa’ba (a cube) containing the sacred stone, what some believe is the burial site of Hagar and Ishmael, and the holy spring—by including several sculptural features, including a fountain, and he anchored the composition in a radial circular pattern, similar to Mecca’s. View of a World Trade Center tower At the base of the towers, Yamasaki used implied pointed arches—derived from the characteristically pointed arches of Islam—as a transition between the wide column spacing below and the dense structural mesh above. (Europe imported pointed arches from Islam during the Middle Ages, and so non-Muslims have come to think of them as innovations of the Gothic period.) Above soared the pure geometry of the towers, swathed in a shimmering skin, which doubled as a structural web—a giant truss. Here Yamasaki was following the Islamic tradition of wrapping a powerful geometric form in a dense filigree, as in the inlaid marble pattern work of the Taj Mahal or the ornate carvings of the courtyard and domes of the Alhambra. The shimmering filigree is the mark of the holy. According to Oleg Grabar, the great American scholar of Islamic art and architecture, the dense filigree of complex geometries alludes to a higher spiritual reality in Islam, and the shimmering quality of Islamic patterning relates to the veil that wraps the Qa’ba at Mecca. After the attack, Grabar spoke of how these towers related to the architecture of Islam, where “the entire surface is meaningful” and “every part is both construction and ornament.” A number of designers from the Middle East agreed, describing the entire façade as a giant “mashrabiya,” the tracery that fills the windows of mosques. In the early ‘70s, as the trade towers were nearing completion, Saudi Arabia was awash in oil revenues, and the state embarked on a massive modernization and building campaign. Yamasaki was premier among the many foreign architects hired during this period. Unwilling to take on too much work, Yamasaki decided to accept just three choice projects in Saudi Arabia: the Saudi Arabian Monetary Agency head office, the Eastern Province International Airport, and the King Fahd Royal Reception Pavilion at Jeddah Airport. In all three projects he continued his explorations in melding traditional Islamic form with modern materials, methods, and functions. As a scion of the Binladin contracting firm, destined to inherit some portion of its vast operations, Osama Bin Laden would certainly have been aware of Yamasaki’s Saudi Arabian projects. Indeed, his family may have built them. (Minoru Yamasaki Associates won’t say, but the Binladens were involved with almost all royal construction.) While Osama was in college in the mid-’70s, Yamasaki was designing his second generation of Saudi work, and the World Trade Center—then the tallest building in the world times two—came to completion in New York. This period was the high-water mark both for Yamasaki’s world reputation and for the Saudis’ national construction plan—which in Saudi Arabia must have brought a heightened sense of importance to the World Trade Center.