Book excerpt: 500 teasing puzzles and conundrums to test your word power and rack your brain with this mixed collection from the MindGames section of The Times, featuring six different types of puzzle. The perfect gift for all word puzzle fans, this collection contains these favorites: - Lexica - 144 letter grid challenges - Polygon - 144 word circle puzzles, how many words can you create? - New Concise Quintagram - 64 new crossword-type challenges. A five-clue quick crossword with one important difference: there is no grid. - New Cryptic Quintagram - 64 new crossword-type challenges. A five-clue cryptic crossword with one important difference: there is no grid. - Word Watch - expand your vocabulary with 96 multiple-choice word quizzes - Codewords - test your powers of logic with 52 word and number grids