Double Trouble Puzzle: A True Brainteaser! This fun and challenging puzzle game features two mazes and two balls. Can you figure out how to remove them at the same time? When you rotate one wooden gear, the other moves, too, but in the opposite direction. A step closer to the exit on one gear may be a step back on the other. A unique puzzle designed by renowned inventor Jean Claude Constantin. Difficulty rating of 4/5 stars. Recommended for ages 14 and up. Puzzle Dimensions: 8" x 4". Overall Dimensions: 10"L x 5"W x 2"H.