One of the two 7-sided star polygons and , illustrated above.
Heptagram
See also
Heptagon, Star PolygonExplore with Wolfram|Alpha
References
Steinhaus, H. Mathematical Snapshots, 3rd ed. New York: Dover, p. 211, 1999.Referenced on Wolfram|Alpha
HeptagramCite this as:
Weisstein, Eric W. "Heptagram." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/Heptagram.html