Beguiling number puzzles that offer a change of pace from sudoku.
Benedek, an Israeli computer scientist and game inventor, offers another passel of hidato puzzles of widely varying difficulty. He starts with a bare-bones rundown of the rules: each hidato is a grid, with some of the boxes filled in with numbers; the object of the puzzle is to fill in the rest of the boxes with numbers that connect in numerical order with two of their neighbors vertically, horizontally, or diagonally. The starting number (always 1) and ending number (the same as the total number of boxes in the grid) are given, and when the puzzle is finished, the numbered boxes form a continuous, meandering pathway of consecutive numbers leading from the first box to the last. Instead of the arithmetical deduction of sudoku, hidato (from the Hebrew word for “riddle”), is more of a workout for spatial reasoning skills; the trick is to figure out the right path through points on the grid from among all the possible pathways. The solution requires imagining how chains of boxes might spread and curve across the page to connect the boxes already filled-in and pruning the many possibilities; the resulting tangle of geometric strategy has something of the feel of a game of go. Benedek includes easy puzzles that will gratify beginners and proceeds to “Medium,” “Hard,” and “Very Hard” levels (solutions are included in the back), ending with two fiendish puzzles labeled “I dare U.” These last are torturous epics that can absorb a puzzler for hours: the experience starts with a baffled search for a foothold; then, a time of exhilaration as numbers come more readily; anxiety and growing frustration as the last, most difficult regions of the grid resist all efforts; a profound exhaustion; rage at the world and all its snares; and finally, a numbed despondency that doesn’t long suppress the hunger for more puzzles.
Amusing and engrossing.