{HEAD ~ The fan blade} is preferably of {TAIL ~ flexible material}, bent to the proper pitch and reinforced with a string or thread stretched across the blade axis and secured to its ends 
{ HEAD ~ The fan blade } is preferably of { TAIL ~ flexible material } , bent to the proper pitch and reinforced with a string or thread stretched across the blade axis and secured to its ends
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL 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