In 1967, a geometrically structured wall first appeared in the work of Hans Peter Reuter. Reuter's "insane tendency towards chaos," as he found about himself, was increasingly overcome by grid surfaces. The tiled walls constitute space with the help of the trompe l'oeil effect of central perspective. The absence of any organic quality leaves with the sterile tiled spaces only the dimensions of space, time and light. Since 1970, the surfaces gridded in such a way have defined empty pictorial spaces flooded with light, which emerge from the central-perspective representation of imaginary floors, ceilings, walls, and masonry. Numerous shades of blue nuanced with white-gray are needed to represent the material-specific reflection of the effect of light. In this way, pictures are created whose characteristic feature, beyond the amazingly pretending, also irritating effect, is above all an aesthetic order based on the color blue.