The myriad layouts that the Panels module comes packaged with are usually sufficient for most requirements. That said, themers wanting to display content using more interesting and complex layouts can also roll their own. While it used to be the case that custom panel layouts needed to be added in as a plugin, this is no longer necessary.
In this recipe, we will make use of the Panel module's Layout designer to create our own custom layout designed for a page requiring a lot of regions.
It is a good idea to sketch an outline of our layout either on paper or in a graphics editor to get an idea of what we want prior to fiddling with the Layout designer. For example, the layout that we are looking to create in this recipe will be based on the rudimentary sketch in the next screenshot which was created using Microsoft Paint: