The present invention relates generally to devices for interacting with {TAIL ~ computer systems}, and in particular, to a device which may be used to render otherwise passive surfaces audiovisually interactive via {HEAD ~ invisible surface codings} 
The present invention relates generally to devices for interacting with { TAIL ~ computer systems } , and in particular , to a device which may be used to render otherwise passive surfaces audiovisually interactive via { HEAD ~ invisible surface codings }
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