The module positions allowing you to have multiple layout configurations. All module positions are collapsible which means if you don't publish any modules in some position it will not take any mini spaces leaving those for neighbor modules. Some positions are designed to arrange modules inside in horizontal layout which makes it very easy to reorder modules inside it.
The layout system is very flexible and capable. Module positions are designed in smart way to cover all possible spot where you might want to put content. More over, you can specify width of both overall layout and specific columns conveniently via template parameters. Bellow is live presentation of some most popular layout variations: