Balance the flat objects to make the outlines of three-dimensional shapes. Triangles can be made most easily; simply balance the ends of two flat objects against one another to form a triangle with the surface they rest on.
Make more complex shapes by standing long, thin objects such as books on their sides. Arrange them into regular shapes like squares, hexagons and octagons. Arrange them so that their ends touch and there is the same angle between the ends of each object.
Pile three-dimensional objects into larger, or more complex geometric shapes. Use books or similar-shaped objects, such as bricks, laying them in rows over each other to make pyramids and cubes.
Use identical objects to learn about tessellation. Tessellation is when sets of identical shapes fit together with no gaps and no overlaps. You will see this in tiling patterns (see Resources).
Fold napkins into equilateral triangles and then arrange them in a tessellating pattern to form larger equilateral triangles. Position two match boxes to form an L shape. Make more L shapes and fit them together.
Look for other approaches you can take by looking at examples of tessellation in the real world. Look for objects around the house that match the shapes in the examples you have found and use these.
Use two identical three-dimensional objects to form the ends of a prism; a solid shape with identical, parallel faces at each end that are joined by rectangles. Lay out the towel, foil other flexible material. Position the objects in opposite corners and parallel to each other.
Make a tube out out of the flexible material, using the objects at each end to give the tube its shape. Pull the material tight around the edges of the objects at each end. Pull the towel tight between the two objects so that it forms straight sides joining the two objects. This will make a prism.
Experiment with twisting the objects at each end while holding the material that joins them tight. See how the sides formed by the flexible material flex and curve.