{HEAD ~ The x ESDS} displace {TAIL ~ both the DES} and UES once they have been used x number of times  
{ HEAD ~ The x ESDS } displace { TAIL ~ both the DES } and UES once they have been used x number of times
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH