Much software design and development is still performed from inside hierarchically structured development organisations. Hierarchy permeates many traditional organisations - the line of military command, the relationship between a surgeon and the attending staff, and the interactions between workers and operations managers on an industrial assembly line are examples. The design of any piece of intellectual property, particularly the design of software, requires interactions and designer-driven flows of information for which hierarchy is considered harmful. This paper considers the nature of software design and addresses the reasons why the supporting organisational structures need to be both flexible and interaction-based. C. Alexander's (1988) analysis of the inappropriateness of hierarchical master-planning in cities and architectural design provides a metaphorical illustration and model. A proposed conceptual solution for dynamic team structuring to support design episodes is described that solves interaction and organisational structuring problems on increasing scales from the individual developer up to the software enterprise level.