The craggy terrain backing Buffalo Bayou in River Oaks near the neighborhood’s decorative gates at Shepherd Dr. sprouted several Usonian-design inspired homes by the architecture firm of MacKie & Kamrath back in the fifties. One of the modernist properties that still remains on the Tiel Way loop landed on the market Monday — and it’s in near original shape, right down to the redwood siding and built-in furnishings. A 1957 structure noted in architectural circles for its angles, wedges, cantilevered terraces, and detail-layered ceilings, the bayou-view home on a ravine lot now bears a $2.5 million price tag.