How do ideas evolve in the context of collaborative design? This research explores the framing strategies and tools involved in the co-construction of a shared understanding in the early stages of a design project. We observed a team of four industrial design students working to design a pop-up shop. We found that, while the key design elements of the solution were present from the early stages of discussion, they were continually framed and reframed through intense verbal discussion supported by sketching reflection-in-action (individual or collective) that help each team member make sense about the pop-up shop branding, user experience, visibility, structure, etc. The design ideas were crystallized at the end of the fourth working session. The research identifies patterns of framing, deframing and reframing of ideas that emerged from different symbolic elements associated with a brand, allowing students to design customized, non-standard, impressive and complex forms. Linking these patterns with specific "designerly actions" led us to develop an empirically grounded model of the framing cycle. This model extends previous work of Schôn and Dorst and Valkenburg to specifically take into account collaborative design situations. In such situations, discussion among team members plays a vital role in clarifying, explaining, and interpreting as well as in encouraging reflection and critique.