{HEAD ~ The method} 7, further comprising sequentially energizing {TAIL ~ the electrodes} to create a traveling wave 
comprising sequentially energizing
{ HEAD ~ The method } 7 , further comprising sequentially energizing { TAIL ~ the electrodes } to create a traveling wave
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH