Edward Powys Mathers was better known to solvers by his puzzle-column pseudonym, Torquemada. Long before he became The Observer’s first cryptic crossword setter, Mathers was experimenting with a stranger form: the crossword in verse, where every clue arrives as a rhyming couplet instead of a plain definition. “Rooks” is one such puzzle from his 1925 collection Crosswords in Rhyme for Those of Riper Years (George Routledge and Sons).