There are tools that let you draw on the screen, no matter what other applications are running. At least there are such tools for Linux, but I'd guess there als

There are tools that let you draw on the screen, no matter what other applications are running. At least there are such tools for Linux, but I'd guess there also would be one for Windows. Heck, I'd guess there is such a tool as a browser bockmarklet. If not, tell me and I write you one (would support Chrome and Firefox and maybe, just maybe, IE11 (canvas+pointer-events:none)).