BrainStrains EyePopping Puzzles Author:Keith Kay, Frank Coussement, Peter De Schepper Mind-blowing conundrums that will sharpen your thinking skills. These fascinating, brilliantly colorful puzzles will strain your brain and dazzle you visually. The picture challenges have a trick to fool you: from vivid optical illusions to 3-D effects. Some problems require a little math but before doing the arithmetic, you ll have to fig... more »ure out the logic underlying the question.« less