Bring the tray of triangles to the work area. Place the triangles on the work area and invite the child to participate in the activity. Take two triangle and slide the sides together. Indicate how the two triangles have now formed a larger triangle. Continue adding triangles until the hexagon is formed. Allow the child to form the new shape with the triangles. Take three of the triangles to form a rhombus (one half of a hexagon). Add three more triangles to form a hexagon. Point out the shape and sides of the hexagon. Allow the child to explore with the triangles. When finished, take the triangles back to the storage shelf.