Since spray cans are associated with data sets, we need to distinguish between private spray cans and public spray cans. Private cans and their spray results are visible only to the creator. This allows members to work independently first to make sure things look correct before broadcasting the can and the results to the whole session. Public cans are accessible by other members of the session. That is, other people can grab and spray someone else's cans. This translates to requests to the remote machine to visualize the remote data set and make the results public.
We also provide a special type of particle/can combination which we refer to as an annotation or pointer can. When sprayed, this can produces a 3D arrow which can be used to point at different locations within the shared virtual workspace. Annotations can also be typed in to label areas of interests.