The Engineer of Playground Pizazz Peter Heuken sees a hillside and thinks of a slide. He spots a stand of trees and envisions a climbing forest. A bridge, to him, looks like a perfect place to hang a swing. But for Mr. Heuken, dreaming up new climbing frames and tree houses is less child's play than German engineering. Playgrounds need wood that won't give splinters, metal to withstand the weather and ropes smooth enough for small hands but strong for safe climbing.