Layouts are what give pages their structure. They define zones that tell where blocks can live on a page. While layouts are assigned to a page they are defined by the theme. We've standardized the name of layouts so when you change the theme of a site, the page knows what layout to use in the new theme. These standard layouts are shown below. By following this pattern, you can update the entire look of your site simply by changing the theme for your site. We know what you're thinking though (because we thought the same way too). You're thinking that there's no way you could possibly limit yourself to these predefined layouts. We think, though, once you understand the level of attention that went into them, you will find that they meet a vast majority of your needs. That said, breaking free of these standard layouts is certainly possible. You can create your own new layout types with their own zone names. You will be giving up the ability to quickly and easily change the look of your site. We'd strongly recommend coloring within the lines until you fully understand the architecture and understand what you’re giving up by breaking free.