I'm sure that this book will be ruined by studying. It's a very shallow and shallow theory, half of the books are problems, and there's no problem, and in between, it's often a misnomer. I admire the courage to make two boards without a black water. There's no solution, there's too many wrong answers, but it's a waste of time to study this book because the theoretical text is so wrong and it'll make sense why it'd be wrong.