Support for work practice is better conceptualised as support for activity taking place in a multidimensional space than as prescription of temporal task sequences. The notion of «common artefact» is introduced to illustrate, unify, and summarise recent research that identifies significant dimensions of cooperative work. Common artefacts may be mundane, everyday objects like hotel keyracks or sophisticated computer tools. Both are multidimensional, in that they provide orthogonal features. They are predictable, help people see at a glance what others are doing (peripheral awareness), support implicit communications through the material being worked on, provide a focus for discussion of difficulties and negotiation of compromises (double level language), and afford an overview of the work process that would not otherwise be available. It is argued that CSCW should support these dimensions of work, rather than trying to anticipate its specific sequentiality.