What differentiates a house designed by architects from a woodland nest built by a robin or a rabbit? That question—and a desire to narrow the gap between the two— inspired the 1,300-square-foot dwelling that architect Keisuke Maeda designed for a teacher, her two teenage daughters, and their cat in the hills of Onomichi, on the southern end of the Japanese island of Honshu. "It’s a nest that’s dug into the ground and covered with fallen leaves, where inside and outside flow into each other," says Maeda. "That seemed right for a house near the woods."