One disadvantage of the phalanx was that it was only effective when fighting in large, open spaces, which left the Romans at a disadvantage when fighting in the hilly terrain of central Italian peninsula. In the 4th century BC, the Romans abandoned the phalanx in favour of the more flexible manipular formation. This change is sometimes attributed to Marcus Furius Camillus and placed shortly after the Gallic invasion of 390 BC; it is more likely, however, that they were copied from Rome's Samnite enemies to the south, possibly as a result of Samnite victories during the Second Samnite War (326 to 304 BC).
Where is the likely source of the change to the manipular formation?
copied from Rome's Samnite enemies

Tarragona has one of the region's most complete ritual sequences. The events start with the building of a huge barrel and ends with its burning with the effigies of the King and Queen. On Saturday, the main parade takes place with masked groups, zoomorphic figures, music and percussion bands, and groups with fireworks (the devils, the dragon, the ox, the female dragon). Carnival groups stand out for their clothes full of elegance, showing brilliant examples of fabric crafts, at the Saturday and Sunday parades. About 5,000 people are members of the parade groups.
About how many people are members of the various parade groups?
5,000

Architects such as Mies van der Rohe, Philip Johnson and Marcel Breuer worked to create beauty based on the inherent qualities of building materials and modern construction techniques, trading traditional historic forms for simplified geometric forms, celebrating the new means and methods made possible by the Industrial Revolution, including steel-frame construction, which gave birth to high-rise superstructures. By mid-century, Modernism had morphed into the International Style, an aesthetic epitomized in many ways by the Twin Towers of New York's World Trade Center designed by Minoru Yamasaki.
What is an example of International Style?
Twin Towers