Thanks for the feedback! I assume this is from the standard mode (not arcade mode). The game flags the line as incorrect as it does not respect the initial positions of the Stones on the Board (so, both negations have to be either red or green). In other words, the lines is correct from a purely logical perspective, however, it does not respect the rules of the level (it is not one of the lines to be found). I should better communicate this in the game, thanks again!