Larsen puzzles feature a frame in which the puzzle pieces can be easily placed time and time again. Each puzzle piece has its own unique shape that fits in only one place in the frame. Because the total thickness of the recycled cardboard in Larsen puzzles is 4.4 mm, they last for years. Various educational frame puzzles are available in the 'Larsen Educational Puzzles' theme: biology, mathematics, geography, learning to write, learning to tell time, etc. Why Larsen? - The youngest children develop their motor skills with the unique puzzle pieces. - Older children also play and learn a lot about interesting themes. - Original themes encourage children and help them concentrate. - Extra thick and sturdy puzzle pieces. - Made in Europe from recycled cardboard.