This app can control home devices and allow them to connect each other; Therefore, the interface design needs a lot of flexibility. Flexibility in user interface design plays an important role.The interface will show or hide the UI element depends on the specifications.For example, some light devices could be turned on / off, controlled colors, changed brightness, and so on. However, some of them are without these function.If UI designer does not keep the flexibility in the beginning of the project, it is hard to extend further function.