What we are talking about here should be the drawing of three coordinate axes in the spatial coordinate system. The coordinate system was founded by Descartes. The coordinate system he founded is Cartesian coordinate system, which is divided into rectangular coordinate system and oblique coordinate system. As for why this is the rule, it may be that it is convenient to combine spatial graphics with algebra when sorting. You can write it down like this and draw the x, y and z axes counterclockwise respectively. Hope to adopt.