Appealing to lovers of brain teasers and crossword puzzles, dot-to-dot activity books are poised to make a big splash in the adult activity book market. Illustrator Adam Turner’s Route 66 designs offer 30 iconic sights from the Mother Road, from The St. Louis Arch to the Cadillac Ranch, in fun-to-solve puzzles. The 500 dots per puzzle are challenging but not impossible, and each puzzle is printed on heavyweight, perforated artist paper that stands up to any drawing medium, even gel pens.