Typical shapes are rectangles, hexagons, and octagons. The fourth basic shape is the polygon, including pentagons and octagons. One has triangles and squares, and the other triangles, squares, and octagons. This excavated cube has 16 triangles, 12 squares, and 4 octagons. Additional regulatory signs are octagons for stop and inverted triangles for yield. Two smaller octagons of similar shape are mounted on top of the main octagon. Figurate numbers representing octagons (including eight) are called octagonal numbers. The ceiling is designed in patterns of octagons and squares. It is illuminated with interlacing octagons and thuluth calligraphy. These carriages are easily identifiable&colon; they are double-decked and are shaped like elongated octagons. They transition from square profiles at their bases to elaborated octagons at their peaks. In particular we can get regular octagons (truncated cube). For example "4.8.8" means one square and two octagons on a vertex. Thomas Jefferson designed and had built two brick octagons at his vacation home. The first has octagons removed, and vertex configuration 4.4.4.6.