Set pupils a project on "making connections", using a sketchbook and a digital camera. Challenge them to record natural forms or phenomena that demonstrate properties such as symmetry and repeating patterns, and related man-made structures and objects that replicate these patterns. For instance, the spiral of a shell might be juxtaposed with a spiral staircase, and so on.
Following this research, show pupils works based on symmetrical mathematical grids, by artists such as Victor Vasarely, Sol LeWitt and Eduardo Paolozzi. Ask them to select a number of paired drawings and images and cut them into squares measuring up to about 8cm. These should be arranged as a square grid, juxtaposing man-made and natural forms.
Photocopy these on to overhead transparencies, so they can be enlarged on to large canvases and used as the basis for symmetrical abstract grid paintings.