mttest, an old XInput test program
I found this in 2012 or so while trying to understand how to add XInput 2.2 multi-touch support to Qt. It's simply a finger-paint program that doesn't depend on Qt, useful for verifying that the touch hardware works, and as reference material when implementing XInput support in libraries. Uploaded to GitHub because I can't find the original source anymore. It started out as the same program that appears here:
but I simplified it a bit since then (you can still see how it was in the git history though).