Dynamic rectangles are any rectangles that are of natural (dynamic) proportions. In other words, these rectangles are full of life in comparison to "static" rectangles. A static rectangle is lifeless. Many people consider a 16×20 rectangle to be static since it does not conform to any of the dynamic rectangles proportions or any possible variation of them. However, add just a small amount to that 16×20 rectangle (less than an inch), and you can make it dynamic, but that is more advanced than what we want to cover today. 

For now, let's just look at some basic dynamic rectangles. These are your "standard" models. With geometry, you can modify these in many different ways to get even more rectangles. We will cover some of those techniques much later. 

Here is a chart showing a few of the most common dynamic rectangles. They can be used for many purposes. For example, you can cut a canvas or sheet of paper to match these proportions with a compass therby giving you a dynamic surface to work on (the kind you see on paintings in museums). Some other tools will help as well such as triangles, t-squares, etc. The actual techniques used to actually contruct these rectangles will be covered in the next article. For now, just look at the size comparisons. They are all drawn to the same height so you can easily compare the width.