Experiences in Grade 8 should be hands-on and experimental, showing transformations in motion, so to speak, with physical tools such as transparencies or with dynamical algebra programs. Once students have a good visual understanding of what the different transformations do, they can start developing the notions of congruence and similarity using them, as in this task. We’ll try to get more Grade 8 geometry tasks up there, but in the meantime it might make sense to look at some of the high school tasks and imagine toning them down a little, such as this one or the various ones attached G-CO.8. I can imagine working with the same basic diagrams here but not getting into the congruence criteria.