Google has a new toy for the development community called Android Design Preview. Design Preview is a tool is software that allows devs and designers to mirror part of their screen onto a USB connected device. The iOS community has had similar apps for some time.
The application requires Android SDK to run. If you don’t know what that is, chances are this won’t affect you. For those it does apply to, the app is free and works on Windows, Mac, and Linux. It is on AndroidDev Roman Nurik’s Google+ page along with a video that introduces the app.