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