Let us pretend that there was a machine, which was constructed in such a way as to give rise to thinking, sensing, and having perceptions. You could imagine it expanded in size (while retaining the same proportions) so that you could go inside it, like going into a mill. On this assumption, your tour inside it would show you the working parts pushing each other, but never anything which would explain a perception. So, perception is to be sought, not in compounds (or machines), but in simple substances. Furthermore, there is nothing to be found in simple substances, apart from perceptions and their changes. — G.W. Leibniz

The inverted machine Rechnender Raum [Computing Space] is a lightweight sculpture, constructed from sticks, strings, and little plumbs. At the same time, it is a fully functional, logically precise, artificial neural network.1 Through its strict geometric and otherwise highly filigreed construction, the observer can track the entire logic circuit from every viewpoint around the machine. This exposure of the machine’s core is reinforced by the uncommon distribution of its constructive elements, with a nine-angled architectural body forming a torus. In contrast to the ordinary arrangement of hidden logic circuits and external, user-facing display, its geometric basis is turned inside-out. The core of the machine, with all its computing elements, is shifted outward, onto the surface, while the “display”, which indicates the results of the tasks, is moved into the center of the system. Even though the tasks and their logic circuits run directly in front of the viewer’s eyes, and even after a long time of contemplating the interaction of the elements that is accompanied by a polyphonic, yet steady and reassuring buzz, it is not possible to grasp the sequence of the machine’s individual conditions. Turning the machine inside out makes its functioning completely transparent, but at the same time it manifests the strict self-referentiality of the machine and its ignorance towards the viewer. The machine turns away from the visitor and carries out its computations only for itself. Without depending on interaction or requesting it, it goes through its own states endlessly. The results of the computations are sent inward—into its own center—they are not intended for the viewer. Hence, an interesting paradox appears: while the machine opens up everything, it closes it at the same time, as though it had a secret. (Georg Trogemann)