Architect Farshid Moussavi is behind a tranquil and timeless new building where Houston’s 40,000-strong Ismaili Muslim community can come together. But how has she created something that looks so delicate out of stone? On a hot autumn day in southern Texas, monarch butterflies flit around the gardens of Houston’s new Ismaili Centre. Fragile and gaudy, they are on their way south to overwinter in Mexico, travelling up to 3,000 miles in a typical migration cycle, an epic feat of insectile endurance. Their combination of delicacy and stamina is an apt metaphor for the Ismaili Centre, a building that has…