In {TAIL ~ some embodiments}, {HEAD ~ multiple portions} of surface 501 are simultaneously exposed to the electromagnetic radiation 
In { TAIL ~ some embodiments } , { HEAD ~ multiple portions } of surface 501 are simultaneously exposed to the electromagnetic radiation
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH