Draw on a sheet of paper several circles, triangles, squares, and then ask your child to paint the red triangles, circles, blue squares and yellow. Then you can complicate the task: draw inside the squares, circles within circles, triangles inside triangles squares. Ask the child to paint them the same colors as in the first case. Each figure should have a two-tone. If a child cannot cope with the complicated job - not a problem: it means that he's too young for this.