This simple idea is perfect for kids. All you need to do are find some stones with interesting shapes in your garden or near your home. Collect the stones and clean them off. Then, take a large sheet of paper and outline the stones.

Next, have the children attempt to match up the stones to the outlines. This is simple, easy and fun for kids and gets them thinking. This is ideal for children ages 3 to 5 years old, allowing them to truly get a sense of depth and perception.