So Linux systems have a common graphical code base, but alternative sets of window managers, look and feel, and development toolkits. As with other areas, we get the double-edged benefits and costs of choice here. There are some really interesting customization opportunities. For unusual systems, such as very large or small or some custom areas, this separation of interface from technology allows great flexibility. Any application can create its own look. So embedded systems can have a simple proprietary look like a TiVo or a high-performance interface like the Sharp Zaurus. We can use this to make a retail or call center application look exactly the way we want. Also, power users can configure their systems as they wish. There are a variety of windowing managers for specialized uses, such as for system administrators or developers.