The dominant Art Deco motif in nineteen thirties America was streamline, and all manner of objects were given streamlined exteriors to look modern. To look modern was to look cool in thirties America. Along side the streamlining, there was a geometric motif, which began earlier, in the twenties. Objects were made in geometric shapes or covered with geometric figures.
The eagle Bookends shown here are composed of triangles, rectangles and trapezoids, all geometric angled figures. Very deco. Angled features were called zigzag deco.
Not all geometric objects were were zigzag. Some were composed of curving geometric figures, like the bookends shown here entitled Rings and Balls, made up in this instance almost entirely of spheres and circular rings.