Why are stairs generally odd?

The number of stairs must be singular. One is that the total number of stairs in a single operation is single; The other is that the total number of stages in each layer is odd. The reason is that people go up the stairs forward, backward, forward, backward and forward. The singular number is "in" and the even number is "out". Therefore, people imply that "gold" means making money and treasures, as well as promoting to a higher position. Coincidentally, in ancient Huizhou residential buildings, most of the stairs were opened on the right side of the painting hall in the main hall. However, in order to get money, some people see water flowing from the left side of their house. Therefore, the stairs are placed upstairs from the left. At the same time, the steps of the stairs are all single (odd) numbers, the odd numbers are days, the stairs are made of wood, and there are slate at the foot of the stairs to form an even number (ground number), which means "heaven and earth are connected". At the same time, the slate resists the stability of the stairs.