These blocks are fun to play with but also incorporate the ability to be able to pop in the sun and learn about beautiful shadows of colours . When the sun hits them they throw a magnificent colour on the floor around them . Add some colour to your block buildings with the Goki Windows Building Bricks. A fascinating play of colours and light shine through colourful, robust windows. The set includes 37 pieces. All GOKI products are designed in Germany and manufactured to strict quality and safety standards, meeting both European and Australian requirements.