The retreat, which was manufactured by Kullman Buildings (founded in 1927 for the purpose of building prefab steel-and-glass diners), takes on an X formation, with one end of the X equipped with floor-to-ceiling glass windows overlooking the water. “It’s quite a bucolic site,” says Garrison. “We related the building to both the lake and the gentle slope of the land, and created an opening in the center of the X that makes the building seem larger and allows reflective light in.”