Frank Lloyd Wright’s neighbor in Oak Park, Illinois, was real estate agent Henry Wallis, who bought land on Delavan Lake and subdivided it into summer cottage lots. George Spencer bought a lot and, on Wallis’s recommendation, hired Wright to design a small house. To fit the long, narrow space, Wright crafted a hipped-roofed rectangular Prairie Style building with a triangular porch pointing toward the lake like a boat’s prow. A wall pierced with art-glass lights unifies the porch and the two-story core. Diamond motifs in many of the windows echo the prow’s geometry. Contrasts in color and pattern add interest to the walls. On the ground level, a continuous dark sill course runs around the building, interrupting the white-painted horizontal board-and-batten sheathing. A second dark stripe separates the first floor from the second, where Wright switched the siding to vertical. The first story’s open floor plan allows space to flow around a brick fireplace. Three bedrooms are upstairs. In 1981, the owners added a two-story guest wing, shaped like the front porch, to the rear of the cottage.