Second time’s the charm for Nadel Architects. The Los Angeles–based firm placed second to Norman Foster in a competition to design Al Faisaliah Tower in Riyadh, Saudi Arabia, 14 years ago. Now the same client, the philanthropic King Faisal Foundation, has commissioned Nadel to design a 2.3 million-square-foot mixed-use building on 10 acres adjacent to Al Faisaliah.

Like its predecessor, the new building features a retail plinth; the two will be connected to form a mega-mall. While Nadel’s project will showcase major evolutions in retail design since Foster’s project was completed, such as atriums that merge retail and upper-level office spaces, it must still accommodate the Saudi custom of keeping the sexes separate. Since women are restricted from tending shop, driving, or eating alongside single men, the complex will include extra drop-off lanes in the parking lot and a segregated food court.

Above the retail plinth, offices will be housed in four glass volumes wrapped in an extra layer of perforated aluminum. The tallest two tower rise 30 stories and curve at their tops like flower petals unfurling; the other pair of towers measure a squat 10 stories each. This design is a careful response to Foster’s pyramid-shaped Al Faisaliah tower nearby. “The stationery, the branding, everything about King Faisal Foundation is based on the icon of the Foster tower,” explains Dan Meis, FAIA, the firm’s former president, who, in April, started his own eponymous firm. “The notion was to create these more organic shapes that embrace the tower rather than muscle up to it.”

The project treats a Kenzo Tange building, which houses the foundation’s offices, less daintily. Its design features two, shallow overlapping triangles with single-loaded office spaces. Nadel is proposing a major renovation that will reshape the floor plate into a more rectilinear form, almost doubling the 755,000-square-foot building, and drape it in a new double-glazed curtain wall for improved energy efficiency.