Book excerpt: The blockbuster Sit & Solve series spins off to the delight of puzzle lovers on the go. Just like the originals, these portable collections feature the highest-quality brainteasers compiled by the top creators--such as Matt Gaffney, the author of dozens of puzzle books. And with these eye-catching shapes--including a coffee cup, subway, bus, and bagel--a trip to the office will never be the same.