* Demonstrate a wide range of triangles in different sizes and orientations. Ask: "Is this a triangle? How do you know it is a triangle?"
* Encourage children to feel for triangles by touch using a feely box or bag
* Make word links. A triangle has three sides and three angles, as the musical instrument with the same name has. A tricycle has three wheels.
* Use the children themselves. Give a rope of old tights to a group of three children. Ask them to move around to make different triangles.
* Use fantasy. How would it be to live in a world of triangles?
* Use construction kits. What shapes can be made using triangles?
* Provide triangular grid paper - children colour larger and larger triangles.