Living structure is a physical phenomenon and mathematical concept, through which the quality of buildings or artifacts can be judged objectively. Living structure is to beauty what temperature is to warmness. Just like a tree, a living structure has two distinguishing properties: “far more small things than large ones” (so called scaling law) across all scales from the smallest to the largest, and “more or less similar things” (so called Tobler’s law) on each scale. Living structure can be only generated in some step by step fashion by two design principles (differentiation and adaptation) through the 15 structural properties.