This paper reports on the learning of spatial concepts in the £o project. The starting point Ls the identification of a visual primitive which appears to play a central role in the visually-based semantics for terms which express spatial relations between two objects. This primitive is simply the orientation of the imaginary ray connecting the two related objects where they are nearest each other. Given this, an important part of the learning consists of determining which other orientations this particular one should align with (e.g. it should align with upward vertical for "above"). These other orientations may be supplied by an objectcentered coordinate frame, as in English "in front of and Mixtec "cii", as well as by the upright coordinate frame. A central feature of the system design is the use of orientation-tuned Gaussian nodes which can learn their orientation and