This paper describes a research-intervention to change technology-enhanced learning (TEL), in a setting of engineering education. It examines how participants used visual forms of mediating artefacts, that is, the means by which the group came together, examined and changed their own TEL activity. Engineering education, an arena that is highly dependent on visualisation and the promotion of visual literacy, largely constrains visual representations to instrumentalist and work-related applications, for the mental rehearsal of engineering solutions. This paper instead describes an activity theoretical perspective, where visual representations of social activity became mediating artefacts, sitting between a collective subject (of learners, lecturers and managers in engineering education) and the object of their activity (to change their TEL activity). In the study described, participants identified, curated and engaged with visual forms of mediating artefacts: stimulating their need and potential for change; assisting their questioning of social conditions and knowledge; and mitigating the reversal and regression of their endeavours. The research-intervention used the Change Laboratory methodology, engaging them in collaborative and agentic double-stimulation tasks through a process of expansive learning. The core claim is that visual forms of mediating artefacts played a crucial role in the group’s qualitatively meaningful change to TEL, and in engendering their transformative agency.