In {HEAD ~ several embodiments} different areas of {TAIL ~ the film} have different thicknesses for producing different interference colors 
In { HEAD ~ several embodiments } different areas of { TAIL ~ the film } have different thicknesses for producing different interference colors
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH