Regular Octagon -- from Wolfram MathWorld

Octagon - Wikipedia

Hexaflake, nflake, pentagonal Tiling, wolfram Research, mathworld, Iteration, tessellation, pentagon, Fractal, geometric Shape

Wolfram Mathworld in the Notebook Archive

What is the definition of a convex polygon? How many vertices does a convex polygon have? - Quora

How to Find the Area of Regular Polygons: 7 Steps (with Pictures)

A Regular Polygon with an Even Number of Sides Is the Union of Rhombuses - Wolfram Demonstrations Project

Smoothed Octagon -- from Wolfram MathWorld

Polygon -- from Wolfram MathWorld

Graham's Biggest Little Hexagon -- from Wolfram MathWorld

A prism with an altitude of 15cm has a base in the form of regular octagon inscribed in a square 10cm x 10 cm. What is the volume of the prism? - Quora

Universal Cover -- from Wolfram MathWorld

Dissecting an Octagon into Four Smaller Octagons - Wolfram Demonstrations Project

Regular Polygon -- from Wolfram MathWorld