Here are some definitions of to tessellate found on the Web:
(1) to cover the plane with a pattern in such a way as to leave no region uncovered.
(2) to decompose a curve or surface into polygonal faces.
(3) to break an image into small, square regions for processing or output.
(4) to tile with tesserae (small pieces used in mosaic work); "tessellate the kitchen floor".
In school mathematics we generally think of tessellating a plane with congruent shapes. But what about tessellating a circle? We could cover it with congruent sectors, which is not very interesting. Below we give a non-trivial way to tessellate a circle with congruent shapes that are not sectors. When cut out, the pieces make a nice puzzle.
Here are some tessellated circles:
Here are some designs you can make with tessellated pieces:
Click on the Flash animation below to view step-by-step how to tessellate a circle: