Bug Link: https://bugs.kde.org/show_bug.cgi?id=478808
Wikipedia Link for Rules: https://en.wikipedia.org/wiki/Mastermind_(board_game) Refer to paragraph starting with "If there are duplicate colors..."
Activity Logic Code: https://invent.kde.org/education/gcompris/-/blob/master/src/activities/superbrain/superbrain.js#L143