Le Corbusier’s small and simple house for his mother on the shore of Lac Leman is one of his least-known works but one of his masterpieces. Its living room feels like a large stateroom in a ship with the water lapping just outside the window, and the overall space abounds in the rhythm taught by Corbu’s mother, a pianist. In keeping with Corbu’s belief that our natural functions should be celebrated rather than concealed, the toilet is directly under a skylight so that sitting on it is to bask in sunshine. Corbu adored “La Petite Maman,” and was determined that she recognize his genius. He advised her to tune in her radio to hear yet again that he was the world’s greatest architect. She replied by asking him why, then, he could not fix her leaking roof. He blamed engineers; he redesigned it; but he never succeeded in keeping the rainwater out. Still, this halcyon dwelling is one of the many treats in a comprehensive exhibition at Bern’s Zentrum Paul Klee, which focuses on Corbu in Switzerland, his birthplace, where he hiked to Alpine peaks as a child and developed the passion for nature that would guide his architecture forever after. —Nicholas Fox Weber