There is a lesson getting from one floor to another here, I am just not sure what that lesson is.The treads are more or less equal in dimension but the risers are not variable, they are random. On the same run of twenty, they can vary from 12 to 2 inches. When going up, the changes in altitude are visible and can be anticipated. On the way down, the disparity is hidden from view, unexpected and lead to vertebrate fusing hits. Landings are complex. Buddha takes wing on flight of stairs.