Or, evolution of the floor. That time and place where floor meant not linoleum, carpet, hardwood, or even dirt, but ants. A bad floor has roughly a 40% mortality rate, most likely due to the additional bad luck of high heels, entertainment centers, and cats. A good floor would be extremely well-organized: the uniformity and tightness of the grid can, at best, create an ant surface tension of 65 Dyne/cm2. All of which is contingent upon the floor having recruited sufficient numbers of ants to begin with. That said, the value of an ant floor depreciates in a sharp slope along the axes of time and wear, while a brand new one can be purchased only on the black market, and only by people who have been carefully screened for ant-corpse allergen sensitivity.