Move Points A and B to explore the figure. Explain why the figure tessellates. The tessellation above is one of the 8 semi-regular tessellations. Semi regular tessellations are regular tessellations of the plane by two or more convex regular polygons such that the same polygons in the same order surround each polygon vertex are called semiregular tessellations, or sometimes Archimedean tessellations.
Weisstein, Eric W. "Semiregular Tessellation." From MathWorld--A Wolfram Web Resource. http://mathworld.wolfram.com/SemiregularTessellation.html