Spatial reasoning is seen as increasingly important in STEM fields. Within mathematics, geometry is a potential site to study and support young children's spatial reasoning. In this paper we revisit Piaget and his colleagues' theoretical perspective on children's development of geometry concepts and take note of projective geometry in that theory. We outline critiques of Piaget and Inhelder's (1967) theory of topological primacy and then situate the criticisms within current spatial reasoning literature. We suggest a return to research on projective geometry holds promise for exploring and expanding opportunities that promote spatial reasoning in the early years.