Unicorns Block Chain is ThinkFun’s newest STEM toys for boys and girls. They are colorful, stylish, collectable brainteasers and among the best gifts you can buy for kids who like smart games and a good challenge. Block Chains are made with high quality components and come with very clear, easy to understand instructions - you'll be able to play within minutes of opening the box. Like all ThinkFun's games, Block Chains are built to develop critical thinking skills. Playing through these addictive brainteasers will improve visual perception, logical reasoning, and critical thinking skills, all through fun gameplay.