This page is designed to allow a perspective grid to be layered over a photo of a winks mat (use “choose file” to pick an image), in order to allow the game state to be described; see Alex’s visualiser for more, or a live webcam version. The image 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 (the example is a really bad case — for your own images, try to get a more side-on view) and the lower image will show the corresponding area warped back to a regular grid.
This should work on a phone — just take a photo, open the page, and select the image you took (which on Android at least is likely the topmost option under “files”). This may be less of a faff than trying to transfer the image between a phone and a computer.
As of 2024, sometime seems to have stopped this from working. I will attempt to debug it at some point; in the meantime, please consider the live webcam version.
Note: Excessive warps may cause the second image to disappear — take a better photo.