1. Ask: How are the shapes in the green circle alike? (They are all circles).
2. Ask: How are the shapes in the black circle alike? (They are all red).
3. Point to the red circle in the part where the circle overlap. Trace your finger around the green circle. Trace your finger around the black circle. Say: This shape is in both circles. Why? (The shape is red like the objects in the black circle, and it is a circle like the objects in the green circle.)
4. Ask: Why are the squares and triangles outside the diagram? (They are not red or circles.)