a repeating geometric pattern.

A regular tessellation is made up of identical regular polygons.

A semi-regular tessellation is made up of two or more different kinds of regular polygons.

And an irregular tessellation is made up of congruent irregular polygons, or even other

shapes.

I’m not going to say much more about tessellations, except to point out that in my opinion, some

of the most fascinating tessellations I’ve ever seen were drawn by M. C. Escher. Go look

him up.