https://www.gkbymrdj.com/some-boys-are-sitting-in-three-rows-all-facing-north-such-that-a-is-in-the-middle-row-p-is-just-to-the-right-of-a-but-in-the-same-row-q-is-just-behind-of-p-while-r-is-in-the-north-of-a-in-which-dir/