Introduction

One way to classify figures is to use a hierarchy. People or groups of items can be organized using this system. In a hierarchy, groups of items are ranked one above the other, based on their properties.

One example of a hierarchy that you may be familiar with is a family tree. A family tree organizes family members based on their parents, siblings, and other family members. The image to the right is an example of a hierarchy in the form of a family tree.