Many excellent examples illustrative of this tendency to modification are found in Pueblo art. Much of the ornament applied to pottery is derived from the sister art, basketry. In the latter art the forms of decorative figures are geometric and symmetrical to the highest degree, as I have frequently pointed out. The rays of a radiating ornament, worked with the texture of a shallow basket, spring from the center and take uniform directions toward the margin, as shown in Fig. 485. But when a similar idea derived from basketry (as it could have no other origin) is executed in color upon an earthen vessel, we observe a tendency to depart from symmetry as well as from consistency. I call attention here to the arrangement of the parts merely, not to the motives employed, as I happen to have no examples of identical figures from the two arts. [Illustration: FIG. 485.--Geometric form, of textile ornament.] [Illustration: FIG. 486.--Loss of geometric accuracy in painting.] It will be seen by reference to the design given in Fig. 486, taken from the upper surface of an ancient vase, that although the spirit of the decoration is wonderfully well preserved the idea of the origin of all the rays in the center of the vessel is not kept in view, and that by carelessness in the drawing two of the rays are crowded out and terminate against the side of a neighboring ray. In copying and recopying by free-hand methods, many curious modifications take place in these designs, as, for example, the unconformity which occurs in one place in the example given may occur at a number of places, and there will be a series of independent sections, a small number only of the bands of devices remaining true rays. [Illustration: FIG. 487.--Design painted upon pottery.] A characteristic painted design from the interior of an ancient bowl is shown in Fig. 487, in which merely a suggestion of the radiation is preserved, although the figure is still decorative and tasteful. This process of modification goes on without end, and as the true geometric textile forms recede from view innovation robs the design of all traces of its original character, producing much that is incongruous and unsatisfactory. The growth of decorative devices from the elementary to the highly constituted and elegant is owing to a tendency of the human mind to elaborate because it is pleasant to do so or because pleasure is taken in the result, but there is still a directing and shaping agency to be accounted for.