Filler, pine panel The drawing might resemble a human brain, but one enclosed by the rectangular borders of the panel rather than by a skull. The folding of the brain’s outer layer allows a much larger surface area to fit within a limited volume. Folding can thus be understood as a transition between a flat surface and a three-dimensional form. According to neuroscientist Anil Seth, perception is a controlled—and controlling—hallucination. It begins with prior expectations that are continuously tested against incoming sensory data through a process of Bayesian inference. One might say that inner assumptions are folded into external impressions, making foreground and background, inside and outside, difficult to separate. Consciousness resides in this ambiguous folded space: simultaneously within us and in the world.