His next major work in Potsdam , the Military Orphanage , was undertaken 1771 - 1778 .
His next major work in Potsdam , the Military Orphanage , was contained a distinctive central block and a spiraling stairwell .
His next major work in Potsdam , the Military Orphanage , was undertaken 1771 - 1778 and contained a distinctive central block and a spiraling stairwell .