Read original post by Matt Cavanagh at RogueCode
[...] The Windows Phone app has two functions; “Live” mode where you move your finger on the screen and the laser will move around in real-time, and “playback” mode when you can first draw something, then hit the play button in the AppBar to playback.
The UI consists of two radio buttons, a really jarring red InkPresenter (I made it so bright to show up nicely on the video), and an AppBar with a play button. The AppBar will only appear when playback is selected.