The melissa and doug mix match stack puzzle is perfect for little hands, with each piece being 18mm thick. The puzzle includes 15-pieces that can be used as a play set too: place a top, middle, and bottom for each space in the wooden playboard to create over 100 possible characters! Or remove the pieces from the board to stack them upright. The sturdy wooden pieces are easy for kids to grasp and stack, nurturing fine motor skills, hand-eye coordination, and imagination, too. There are loads of extension activities to do as well, for example: point to each assembled person ask you help the child identify and describe each person they created. Switch several of the pieces so the outfits are mismatched. Then ask the child to put the people back together the correct way. Ask the child to group the pieces by size. Ask questions to help the child make observations about the pieces: "do the smallest pieces go on the top or the bottom of the people? Is the tallest piece also the widest?"