Enhance Natural Learning Progressive Design Playgrounds' Outdoor Learning Environments extend the classroom into the outdoors, allowing children to explore their surroundings with sight, hearing, touch and smell. Natural elements, such as sand, water and living plants enhance the learning experience. Playgrounds are available in different configurations, such as vegetable gardens, mazes, greenhouses and slides built into grass hills. (415) 437-0437 / www.pdplay.com