They look at the bandstand design, which is a regular hexagon. Ada gives the children more examples of regular and irregular polygons to sort, and they talk through their reasoning.

Irregular polygons are shapes that have sides and angles of different sizes. You can always identify the polygon by how many sides it has. For example a pentagon is always a shape that has 5 sides.

The researchers extended a triangular motif into (3, 3)-type six-connected building block to form an irregular hexagon.

The researchers extended a triangular motif into (3, 3)-type six-connected building block to form an irregular hexagon.