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-DMoreMind-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 figure out the logic underlying the question.