This paper presents a framework for analysing perceptual Twin Earth thought experiments. Visual content normally has an analogue character, and it is argued in this paper that this sets certain constraints on the extent to which Twin Earth thought experiments can be successful. The argumentation in the paper is developed by using examples from visual spatial content. It is argued that visual spatial content can only be "twin-earthed" in a very limited way. Whereas the metrics of space can be twin-earthed, visual experience has a structure that means that it can only be the vehicle for representing entities with geometrical structures.