5 Spy Wall	• • • •	Crisscrosser: Rhomboidal openings serve as rungs and encourage the perception of one's own body. Flash-Puffs: Set particles in motion through invisible and noiseless air streams and marvel at the haphazardly emerging flashes. Spy Cell: Sharpen the senses, become sensitized to the surrounding space. Two-Sidedness: The elevated point of observation plays an important role in the geography classes as an illustration for the bird's-eye view.