From: The World In Your Head by Steven Lehar

Fig. 7.4 (A) If the model world incorporated a curvature, like a gyrus in the cortex (or, viewed from the other side, like a cortical sulcus), this curvature too would not be apparent to the little man within the model world. (B) From the internal world looking out, an inverse curvature would be observed. This can be understood intuitively by imagining that the model and the pedestal in (A) are elastic, and considering what kind of deformation of the pedestal would be required to straighten out the curvature in the model space.