1. A method of dividing a task amongst a plurality of nodes within a distributed computer, said method comprising: operating each of said plurality of nodes, each of said nodes having recorded therein graph data representing a task-suited logical network comprising a plurality of nodes and the links between them, to receive immediate neighbour requirements data indicating desired properties of immediate neighbour nodes in a task-suited logical network of nodes and interconnections between them, which properties lead to said task-suited logical network being suited to said task or tasks of a similar type, said requirements data including distinctive immediate neighbour requirements data indicating desired immediate neighbour properties which differ from immediate neighbour properties for one or more other nodes; receive node capability data from an applicant node available to join said task suited logical network; determine whether to allow said applicant node to become an immediate neighbour in dependence upon said distinctive immediate neighbour requirements data and said node capability data; and update said stored graph data on deciding to grant a task-suited logical network connection request received from an applicant node, send a response to the applicant node sending said request indicating that said request was successful, and distribute said task amongst the plurality of nodes in accordance with the task-suited logical network topology thus determined.