“Scratchy Cloak of Darkness” is based on the “Cloak of Darkness” specification — a very simple pattern, designed to help programmers compare the strengths and weaknesses of various coding environments. “Cloak of Darkness” is not going to win prizes for its prose, imagination or subtlety. Or scope: it can be played to a successful conclusion in five or six moves, so it’s not going to keep you guessing for long.…