The steps of the stepped land for ordinary duplex small villas in Yunnan shall be connected by slope protection or retaining walls. When the height difference between adjacent terraces is greater than 1.5m, safety protection facilities shall be added on the top of the retaining wall or slope protection with a slope ratio greater than 0.5; The two are combined into a duplex, with basic spaces such as bedroom, living room (hall), kitchen and toilet, and the clear height from the window sill of the external window to the floor and ground is less than