The Croquet Project is an international effort to promote the continued development of Croquet, a new open source software platform for creating deeply collaborative multi-user online applications. It features a network architecture that supports communication, collaboration, resource sharing, and synchronous computation among multiple users. Using the downloadable Croquet SDK, software developers can benefit from a flexible enough framework that virtually any user interface concept could quickly and easily be prototyped and deployed to create powerful and highly collaborative multi-user 2D and 3D applications and simulations.
-- http://en.wikipedia.org/wiki/Croquet_project

Croquet is a combination of computer software and network architecture that supports deep collaboration and resource sharing among multiple users within the context of a large-scale distributed information system. Along with providing a flexible enough framework that virtually any user interface concept could quickly and easily be prototyped and deployed, Croquet can be used to deliver compelling 3D collaborative visualizations and simulations.

Croquet incorporates replication of computation (both objects and activity), and the idea of active shared subspaces in its basic interpreter model. More traditional distributed systems replicate data, but try very hard not to replicate computation. But, it is often easier and more efficient to send the computation to the data, rather than the other way round. Consequently, Croquet is defined so that replication of computations is just as easy as replication of data.

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