(
 (prefix ((: <http://example/ns1#>))
   (tag 
     (triple :x :p 1)
     (triple :x :p 2)
     (prefix ((: <http://example/INNER#>)
	       (x: <http://example/X#>))
       (triple x:x :p 2)
       ))
   )
 (prefix ((: <http://example/ns2#>))
   :x
   )
 (prefix ((: <http://example/ns3#>))
   )
 )