(_ββ_) In the _second_ place, however, the exterior begins to make itself at the same time intelligible to itself[107] in this close association with the form and subdivision of the interior for the very reason that it has its own peculiar tasks to fulfil. In this connection we may mention the _flying buttresses._ They represent the position of the many piers within the building and are necessary as points of support for the elevation and security of the whole. At the same time they further make apparent on the outside, so far as interval, number, and other features are concerned, the rows of piers on the inside, albeit they do not exactly reproduce the shape of the interior piers, but the higher they mount up become reduced in the strength of their springing buttresses. (_γγ_) Inasmuch as, however, in the _third_ place, it is only the interior which has to be one essentially complete enclosure, this feature is lost in the form of the exterior and makes way in every respect for the all-prevailing characteristics of continuous elevation. And for this reason the exterior receives at the same time a form independent of the interior, which asserts itself mainly in a tendency to strive upwards on all sides into points and pinnacles, breaking out in them one on the top of another. To this fundamental feature belong the lofty uplifted triangles which, independently of the pointed arches, soar upwards over the portals, pre-eminently the principal façade, though also over the colossal windows of the nave and choir, and in a similar way the slenderly pointed shape of the roof, whose gable-end is especially prominent in the façades of the transepts. Add to these the flying buttresses, which everywhere terminate in little pointed pinnacles, and in this way, just as the rows of piers within the building create a forest of stems, branches, and vaultings, on their part on the exterior stretch up heavenwards a forest of points.