Correa describes how his cultural centre in Jaipur, the Jawahar Kala Kendra, is based on the concept of the Navagraha, the mandala of nine planets fundamental to Hindu astrology. An early sketch next to an enigmatic wooden model shows how the grid of nine planetary squares houses the galleries, theatres, museums and auditoriums, with the corner square mysteriously rotated to create an entrance.
"Every society has seen architecture as something that transcends its functional role, as a diagram of the cosmos," he says. "But now we have become too mundane about what we build; we can make things that are whimsical, but not profound."
One unusual model in the gallery upstairs shows when he himself strayed from his own principles in a temporary project for an industrial trade fair in 1961. The faceted concrete planes of the Hindustan Lever pavilion look like a crumpled sheet of card, foreshadowing the work of deconstructivist architects by more than two decades. But it was not an avenue he was keen to pursue. "This way lies madness," he grins, tapping the wonky wooden model. "It's like writing Finnegans Wake: Joyce lost his audience, and then he lost himself. The more you do things like this, the more they are the same. I'm glad I stopped."
For Correa, successful buildings must be tied to their context above all. "Architecture is not a moveable feast, like music," he says. "You can give the same concert in three different places, but you can't just repeat buildings and clone them across the world."
Unlike many of his generation, he refuses to "get off a plane and design", and, while he has built experimental housing projects in Peru and a biomedical research centre in Lisbon, he refuses to describe himself as an international architect. Nor does he see his buildings and the 6,000 drawings he has donated to the RIBA archive – half a century of work – as anything more than "the trail that a snail leaves in its wake as it inches forward."