In {HEAD ~ one approach} a solid metal disk has {TAIL ~ blades} machined from its periphery 
In { HEAD ~ one approach } a solid metal disk has { TAIL ~ blades } machined from its periphery
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH