The big change is happening because Google's new design language called Material Design.
Senior Vice President of Google for Android, Chrome and Apps, Sundar Pichai said, is to make changes to the look of Android L is quite different with Android version 4.0 (Ice Cream Sandwich) which slide in 2011.
Android L offers a new look flat and simple interface with elements rounded and soft edges. More than that, Google also includes animation runs smooth in transition.
We also invite application developers to beautify the look of their applications with depth effect, splashes of color, and shadow.
In the new version of Android, users can interact directly with the notification that appears on the screen is locked.
There is also a new interactive notification system called heads-up notifications. This feature is able to work when the user is playing games and appeared incoming calls. Well, this incoming call notification will appear at the top of the screen, then the user can completely ignore, accept or close calls.
Materials Design is not just intended for Android L, but also be applied to the operating system Chrome OS and Google's services on the website. This step shows how Google wants to provide a consistent experience to users.