In ancient China, odd numbers were regarded as positive numbers and even numbers as negative numbers. The sky is Yang and the earth is Yin. People think this is auspicious.

The number of stairs is generally odd, which is in line with people's habits. The first step is the same as the last step, which makes people more natural. When going up the stairs, the steps can be odd or even. The human body has a suitable range for the plane size and cross-sectional size of each stair step, and the architect determines how many steps to choose according to the comprehensive balance of the plane size and cross-sectional size of the building. The so-called "comprehensive balance" is more about the different needs of users. For example, the stairs in a factory workshop are obviously different from those in general public facilities, which is determined by the difference in the applicable scope of adults and children. Generally speaking, in the content of comprehensive balance, the problem of single step or double step is rarely considered, but because the architectural design basically conforms to the architectural module, odd stairs are mostly, and even stairs are still rare.