| 
 | 
 | 
257 is a Fermat Prime, and the 257-gon is therefore a Constructible Polygon using Compass and
Straightedge, as proved by Gauß. 
  An illustration of the 257-gon is not included here, since
its 257 segments so closely resemble a Circle.  Richelot and Schwendenwein found constructions for the 257-gon in
1832 (Coxeter 1969).  De Temple (1991) gives a construction using 150 Circles (24 of which are
Carlyle Circles) which has Geometrography symbol 
 and
Simplicity 566.
See also 65537-gon, Constructible Polygon, Fermat Prime, Heptadecagon, Pentagon
References
Coxeter, H. S. M.  Introduction to Geometry, 2nd ed.  New York: Wiley, 1969.
 
De Temple, D. W.  ``Carlyle Circles and the Lemoine Simplicity of Polygonal Constructions.''  Amer. Math. Monthly
  98, 97-108, 1991.
 
Dixon, R.  Mathographics.  New York: Dover, p. 53, 1991.
 
Rademacher, H.  Lectures on Elementary Number Theory.  New York: Blaisdell, 1964.