八角星,又称八芒星,是一种有八只尖角,并以八条直线画成的星形。
几何学
在几何学中,八角星是边自我相交的八边形。
正八角星只有两种,其施莱夫利符号计为{8/3},与所述第二数字差别在绘制八角星时顶点间隔数,若计为{8/1}则为正八边形,一般会省略后半只计{8},此外,若计为{8/2}则为两个正方形的复合形状,并且两个正方形之差相差45度角,若计为{8/4}则为四个退化多边形正二边形的复合形状。
底面为正八角星的棱柱、反棱柱
正八角星{8/3} |
八角星柱 |
八角星反棱柱 |
八角星交叉反棱柱 |
参考文献
- Grünbaum, B. and G.C. Shephard; Tilings and Patterns, New York: W. H. Freeman & Co., (1987), ISBN 0-7167-1193-1.
- Grünbaum, B.; Polyhedra with Hollow Faces, Proc of NATO-ASI Conference on Polytopes ... etc. (Toronto 1993), ed T. Bisztriczky et al., Kluwer Academic (1994) pp. 43–70.
外部链接
- 埃里克·韦斯坦因. Octagram. MathWorld.
- https://web.archive.org/web/20151104130338/http://home.hiwaay.net/~jalison/hepta.html Approximate construction method]
参见
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