Grimm's Colored Cards for Building in Storage Box - "Beer Mats" Construction Toy/Accessory Includes 40 cards ("beer mats" = similar to coasters) 20 different colors included (one pair of each color) Made of MDF, a wood composite, so they are stiff (not flexible), making them ideal strong surface for building/stacking Extend the possibilities of almost any set of building blocks you already own Children will come up with many imaginative ways to use these cards: build a "road", stack with blocks, "roofs" for doll structures, etc.