And yet, in a series of works of art among the most magnificent that man possesses, this miracle was achieved. The Greek temples and Gothic cathedrals are so much alive that they seem not to have been made with hands, but to have grown. The straight lines have been modified into delicate curves, the angles have given place to arches, the stiff and mathematical have been molten into movement and surprise, the heaviness has been so nicely balanced or overcome that it has been changed into lightness, with the help of human and animal sculpture and floral carving the inorganic has been transformed into the organic, by means of painting and stained glass even the dull surfaces of walls and windows have been made to glow into life. Artists wrought each portion and detail, and built the whole for the glory of God and the city, a monument for quiet contemplation, not a mere article to be used. With few exceptions, any architectural beauty that we create is but a feeble echo of theirs. Some day we may be able to produce something worthy to be placed by its side, but only when we have sanctified our life with communal aims. The aesthetic effect of a building depends upon many factors, of which only a few can be analyzed by us in this short chapter. If we abstract from its relation to purpose, architecture is fundamentally an art of spatial form. Working freely with it, under the sole limitation of function, the architect can make of this form a complex, various, and beautiful language intelligible to all men, and possessed of a systematic, yet fluent logic. Of this language the simplest element is line. At first view, as we approach a building from the outside, its beauty, as in the case of sculpture, is essentially pictorial. For, although a building is a three-dimensional solid in reality, each view of it is a two-dimensional surface, bounded by lines and divided and diversified within by other lines. Now these lines have their life and beauty like the lines of a picture. How they get this life and what its specific quality is in the case of particular lines, we need not explain again; but no one can fail to feel the upward movement of the vertical lines of the Gothic style, the repose of the horizontal lines of the Renaissance style, the playful grace of the Rococo. Naturally, since the front of a building, where one enters, is the most important and the most constantly in view, its pictorial beauty is elaborated with especial care by the architect. This is the justification of the overshadowing preeminence of the facade in Renaissance palaces, which indeed was oftentimes the only visible part of the outside of the building. When, however, the building is perspicuous all round, it should, like a statue, present a beautiful view from every standpoint.