When one takes a pen, trys to write but it does not work. so they take the pen and go to a scrap sheet of paper, or at the top/bottom of the page, and do a scribble, to get the ink flowing. The mark that they make is known as a scren (scribble + pen).
Person 1: Here, please sign this check.
Person 2: *trys to sign, but doesn't work* Oh god, *sweats* *goes to random sheet of paper and creates a scren* *signs document* here you go.
Person 1: Thanks, bye.