This article gives an wonderful insight into students working on the Arclets problem that first appeared in the Sept 2002 edition of the NRICH website.
Show how this pentagonal tile can be used to tile the plane and describe the transformations which map this pentagon to its images in the tiling.
Polygon Pictures
Age 11 to 14 Challenge Level
Start by writing down all the angle facts and rules you can think of that might be useful.
What do you know about the angles in regular polygons?
What shapes are formed by the overlaps?