The visitor is received into a completely dark, acute-angled triangular space of aluminium plates on a steel-girder construction. The only light source is a 5 m by 3.75 m (16ft by 12 ft) screen which is the transparent side of a real environment which will present other, virtual worlds. This environment's ground plan is by architect Christian Möller and is based on a design typical for this area, the saddle-roofed 'St. Nicholas House' style. The screen is on the left-hand side of the roof onto which images are rear-projected from a wide-screen CAD data projector. The visitor enters the darkened space, and the game begins. The floor is filled with grey and colored spots (pressure pads); he must decide whether to avoid the colored spots and stay firmly rooted in the real world, or step on one and enter one of several virtual environments. The chosen environment can be navigated by stepping on the remaining light gray dots. So the visitor has three virtual worlds to choose from: the world of text (in cooperation with Bob O'Kane, Constanze Ruhm), the world of space (with Christian Möller, Dieter Beck), and the world of objects (with Akke Wagenaar). If he has entered a world mode, he walks on the grey dots to control appearance, form, and shape of each world, not only dialing the codes of the world modes but also playing around with the modules of these codes as he progresses. His steps evoke changing images of these worlds that are projected in real time onto the screen.