Research on geometric transformations suggests that early learners possess intuitive understandings grounded in motion metaphors, transitioning to mappings. The processes through which students transition between these two conceptions are not fully understood. We propose that Vygotskian hybridizing (related to Vygotsky's articulation of everyday and scientific concepts) may provide a lens for thinking about the relationship between these conceptions. Design features of block-based programming environments provide affordances to support hybridizing by providing a co-action space for learning. We conducted a comparative case study of four grade seven and eight students working in a Scratch task (Code the Quilts) and a game (Transformations Quest) to construct understandings of geometric transformations. Our findings suggest: (1) students hybridized their personal experience of motion and mathematical knowledge of mapping to build geometric transformations understandings and (2) the co-action space in which students worked promoted distributed interactions between students, block-based environments, and tasks to support hybridizing.