Larsen's puzzles have a frame in which the puzzle pieces can easily be placed again and again. The puzzle pieces each have their own unique shape that only fits in one place in the frame. Because the total thickness of the recycled cardboard of the Larsen puzzles is 4.4 mm thick, it will 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 the children and help them concentrate. - Extra thick and sturdy puzzle pieces. - Made in Europe from recycled cardboard.