While the same rectangular idea predominates in figure 303, it is worked out with the introduction of triangles and quadrilateral designs. This fairly compound pattern, however, is still classified among rectangular forms. A combination of rectangular and triangular geometric designs, in which, however, the former predominate, is shown in figure 304, which can readily be reduced to certain of those forms already mentioned. The triangles appear to be subordinated to the rectangles, and even they are fringed on their longer sides with terraced forms. It may be said that there are but two elements involved, the rectangle and the triangle. [Illustration: FIG. 305--S-form with interdigitating spurs] The decoration in figure 305 consists of rectangular and triangular figures, the latter so closely approximated as to leave zigzag lines in white. These lines are simply highly modified breaks in bands which join in other designs, and lead by comparison to the so-called "line of life" which many of these figures illustrate. [Illustration: FIG. 306--Square with rectangles and parallel lines] [Illustration: FIG. 307--Rectangles, triangles, stars, and feathers] The distinctive feature of figure 306 is the square, with rectangular designs appended to diagonally opposite angles and small triangles at intermediate corners. These designs have a distant resemblance to figures later referred to as highly conventionalized birds, although they may be merely simple geometrical patterns which have lost their symbolic meaning. [Illustration: FIG. 308--Crook, feathers, and parallel lines]