As iPhone apps mature, designers are exploring new navigation structures that can support an increasing breadth of content while keeping simple tasks accessible. There are now many examples of custom navigation, such as TweetBot’s flyout menus and Twitter’s label-less, contextual tab bar. A budding navigational design pattern that is growing in use is the custom center tab button. In this approach, app designers centralize their app’s primary tasks or content under the middle-most button of a standard 3- or 5-button iPhone tab bar. This “focal button” provides a way to indicate and drive users to the primary functionality of the app, allows for top-level awareness of secondary content sections, and doesn’t require as much re-learning as a completely custom navigation design. To differentiate the focal button from the other tabs, it is typically given a special visual treatment and an action label (ie, “Check In” or “Scan” vs. “News” or “Featured”). Its visual emphasis helps users quickly recognize the core action they need to take, while its location, directly above the iPhone’s hardware home button, gives it a natural physical reference point.