Melissa & Doug Sort, Match, Attach Nuts and Bolts Boards Twisting together these oversize nuts-and-bolts pairs is so gratifying, parents will find themselves pairing them up along with their preschoolers. Cast in three different shapes and colors, the plastic pieces add the finishing touch to 12 picture puzzles on six double-sided wooden boards. The challenge: Piece together the nuts-and-bolts duos that complete the pictures on both sides at once. It's a great hands-on challenge to growing cognitive skills and a motor-skills booster, too.