Write some simple rules about what constitutes tessellation and what does not at the top of the page. Include the facts that the patterns must join together with no gaps and no overlaps. Explain that the shapes must be regular, that the pattern must be repeatable forever but that you can use more than one type of shape.
Draw or photograph and paste examples of patterns that show tessellation and patterns that do not. Label them to show what rules they are holding to and what rules they are not.
Challenge the students to use the plastic geometric shapes as templates to draw a tessellating pattern. Provide a box in which they can draw the pattern.
Provide some more examples of tessellating and non-tessellating shapes. Ask the students to identify the non-tessellating ones and give reasons why the shapes do not qualify.
Ask the students to give a list of places they might have seen tessellating patterns, either in the natural world or the man-made environment. Write that tessellating patterns are often very strong and show a picture of a brick wall or geodesic dome. Ask the students if they can think of other reasons why you might want to build with tessellating patterns.