This page is designed to allow a perspective grid to be layered over a live video of a winks mat, in order to allow the game state to be described; see Alex's visualiser for more, or the static version to work with still images. The video is not actually uploaded - everything stays in the browser. Drag the control circles to align the grid on with the mat in the upper image and the lower image will show the corresponding area warped back to a regular grid.
This should work on a phone - you might need to change the "video source". Not all devices or browsers support web cam access, however.
Note: Excessive warps may cause the second video or grid to disappear - put the camera somewhere better.
Note: Depending on your system, front-facing/webcams may be horizontally flipped. Make sure you know what you're looking at when telling people coordinates.