Totally Tough Brainteasers

To solve these inventive brainteasers, your brain has to be in tip-top shape. Warm up with some (slightly) easier puzzles: beginning in the left corner of a box with grids, try to reach the bottom right square. You may pass only through the left and right sides of small squares, but not through their top or bottom. And you can't go through the black squares at all. Another challenge involves four dice, all stacked up. Can you find a pattern that lets you figure out how many pips are on the base side? Arrange the "magical dominoes" precisely and mathematically; do the equations to figure out how. There are also unusual card tricks, "cut-it" puzzles that involve reconstructing figures that have been broken up, and three-dimensional conundrums. As you work each one out, you'll feel yourself getting smarter every minute.