Much of the knowledge used within an XP team is tacit, i.e. it is hidden and intangible. Two tangible artefacts that carry information about the team?s work are the index cards which capture stories and tasks to be implemented and the wall where they are displayed (which we refer to as the ?Wall?). It is widely acknowledged that these are key elements supporting the work of the XP team, but no systematic investigation of their role has been reported to date. In this paper, we focus on the use of these artefacts within one XP team. We use distributed cognition, a framework for analysing collaborative work, to explicate the information flows in, around and within the team that are supported by the index cards and the Wall. We then interrogate the models produced using this analysis to answer ?what if? questions.