---                                     
                    -        --                             
                --( /     \ )XXXXXXXXXXXXX                   
            --XXX(   O   O  )XXXXXXXXXXXXXXX-              
           /XXX(       U     )        XXXXXXX\               
         /XXXXX(              )--   XXXXXXXXXXX\             
        /XXXXX/ (      O     )   XXXXXX   \XXXXX\
        XXXXX/   /            XXXXXX   \   \XXXXX----        
        XXXXXX  /          XXXXXX         \  ----  -         
---     XXX  /          XXXXXX      \           ---        
  --  --  /      /\  XXXXXX            /     ---=         
    -        /    XXXXXX              '--- XXXXXX         
      --\/XXX\ XXXXXX                      /XXXXX         
        \XXXXXXXXX                        /XXXXX/
         \XXXXXX                         /XXXXX/         
           \XXXXX--  /                -- XXXX/       
            --XXXXXXX---------------  XXXXX--         
               \XXXXXXXXXXXXXXXXXXXXXXXX-            
                 --XXXXXXXXXXXXXXXXXX-
				 
I have a radical idea. The door swings both ways. 
We could reverse the particle flow through the gate.