{HEAD ~ Subsequent layers} are spun onto {TAIL ~ the top surface} of prior layers and exposed, and upon completion of the succession of layers each defining corresponding levels of the desired structure, the layers are all developed at the same time leaving the three dimensional structure 
are spun onto
{ HEAD ~ Subsequent layers } are spun onto { TAIL ~ the top surface } of prior layers and exposed , and upon completion of the succession of layers each defining corresponding levels of the desired structure , the layers are all developed at the same time leaving the three dimensional structure
HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH