Built on spec, this house is for another kind of speculating, as well. This peaceful enclave near the beach is perfect for thinking, wondering, hypothesizing. The house is organized around a central stair tower that offers views as one ascends. At the top is a room for speculation with views to every direction and access to a dramatic roof deck. To the left of the tower are functional rooms on two floors — kitchen, dining, bedrooms. On the right is a lofty great room.