For this activity, you take a piece of paper and fold it in half, hot dog style. You can print something on the paper like this one is, or you can just as easily write on it. Draw or print lines between the shapes and either you cut or have your child cut the lines between the shapes.
Find pictures of shapes. These could be printed, drawn, or from magazines. Have your child cut and glue them inside the hot dog paper, so if your child opens the circle flap, she will see the things with circles. This picture shows the flaps all open so you can see what is there.
Simple, fun, and effective!