Building upon the wonderful foundation of unit blocks by providing children with a themed exploration set, Block Mates are designed to enhance the original principles of block-building. They are engineered to fit in standard unit blocks and can be built in their natural form or mixed and matched with others in the set to create new, imaginative vehicles or creatures. Our unique gasket design ensures a snug fit. Blocks not included. Set features five familiar farm animals: pig, horse, cow, goat and sheep. Ages 3+.