Stapelstein are a German company who make modular play toys. When you first see them, they look very simple. However, these durable, stackable pieces are some of the greatest open-ended toys around. Their toys are designed for creative, open-ended play and awesome for stacking, balancing, and spinning, both indoors and outdoors. We love them because they're non-toxic, water-resistant, and safe for children, while also supporting the development of motor skills, balance, and imagination.