Great fixity of design appears also in the rawhide boxes of the Sauk and Fox Indians, to which I referred before (p. 25 et seq.). The characteristic feature is the division of the rectangular hide that is to form the box, into three fields lengthwise, five fields crosswise. The five fields are determined by the way in which the box is folded; four sides forming front, bottom, back and top, and the fifth a flap covering the front. The lengthwise division is not so determined, for the width of the box differs considerably from that of the central field. The design elements are based on common patterns of the Indians of the northern part of North America: rectangles divided by central longitudinal lines and obtuse triangles on each side of it. It should be noticed that the design unit is not the diamond but the rectangle with two obtuse triangles that have the apex near the central dividing line. This appears clearly in the specimen shown in fig. 144 _b_ in which every design begins at the margin with a triangle pointing inward towards the opposite triangle and also in the other figures in which, in accordance with the art style of the eastern woodlands, a segment is substituted for the acute triangle. A second element in these designs is the acute triangle with lines, or a single line, extending from the apex; a form which is also common to all the woodland and plains Indians. [Illustration: Fig. 144. Painted rawhides, Sauk and Fox.] [Illustration: Fig. 145. Painted rawhides, Sauk and Fox.]