Both the nature of many products and their process of creation are becoming increasingly digitally mediated. However, our bodies and minds are naturally conceived to interact with the physical, so crucial design information can be elicited by constructing meaningful prototypes. This paper examines how physical materials impact early design through a study that explores how groups with very different materials tackle a common design challenge. The inherent physical properties of the materials and the ways in which designers interpret and manipulate them give rise to subtle patterns of behaviour. These include the ways in which groups move between abstract and concrete discussions, the way groups comply with or resist the materials they are given, and the complex interactions between the physicality of materials and the group dynamics. This understanding is contributing to our research in explicating the fundamental role of physicality in the design of hybrid physical and digital artefacts.