"L," "I," "T," and "S" are the names of four shapes known as tetrominoes--polygons created by joining four squares together. Put them all together (if you can) and you get LITS--the newest idea in brainteasers from the puzzle wizards at Nikoli. In each puzzle, there's just one way to fit the tetrominoes into the grid areas so they all connect correctly. Solvers won't be able to resist taking the challenge. The dozens of teasers here guarantee hours and hours of entertainment--and also offer the kind of mental exercise proven to keep the brain sharp for a lifetime.