There are 40 natural and color blocks come with wooden balls. This set includes special accessory to construct windmill. It is compatible with PlanToys Construction Set. PlanToys creates toys that inspire children's imagination as well as promote their physical and intellectual development. We're also proving that it is possible to maintain superior quality standards while steadfastly following path of environmental and social responsibility. PlanToys practices the Three R's of green living: Reduce, Reuse, and Recycle. Our manufacturing processes are designed to reduce waste and save energy. We reuse materials, and have introduced innovative methods to recycle paper and other products. We are always looking for new ways to improve and preserve our environment. Our uncompromising quality is accomplished by the work of our management team; our experienced designers; and our manufacturing, packaging and shipping personnel. At every step of the way we are meticulously dedicated to process that ensures children's safety.