“Are you sure it’s a boomerang?”

Abstract This study explores how pairs of students use the task input (instructions and laminated pictures) while engaged in an open-ended problem-based oral task in English as a Foreign Language. Framed within the current interest for materials use in the L2 classroom, our work contributes to task-based language teaching research with its ethnomethodological, conversation-analytic approach. Fine-grained, multimodal analyses of the students’ task-based interactions show that: (a) they search for a solution that fits all items on the pictures and is congruous with the scenario in the instructions; (b) they orient to the visual appearance of the items; and (c) the materiality of the task input affords embodied actions that foster intersubjectivity and task progressivity. The study also has pedagogical implications in relation to task design.