{HEAD ~ The teeth} project in {TAIL ~ the same direction} as the flange of the helix to which they are attached 
project in
{ HEAD ~ The teeth } project in { TAIL ~ the same direction } as the flange of the helix to which they are attached
HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH