About 50 miles northwest of London, an eye-catching building has taken root. It’s MK Gallery, the “MK” standing for British town Milton Keynes, and it’s the work of 6a Architects, a practice known for its contemporary art galleries, particularly in historic environments. Which applies to this project, as the firm’s contribution is an addition to an original 1990s structure by Andrzej Blonski Architects, and brings the gallery’s new square footage to nearly 5,400. Some original elements were retained, but the facade, panels of corrugated steel interrupted by an enormous, sun-reminiscent circular window, is purely 21st century. Inside, however, the vibe skews slightly ‘70s, thanks to artists Gareth Jones and Nils Norman, who selected the color palette. They then collaborated with graphic designer Mark El-khatib on the public spaces, such as the Sky Room auditorium and the café, where saturated red and yellow pop against the white-and-gray concrete and tile envelope. Currently on view in the galleries is “Paula Rego: Obedience and Defiance,” until September 22.