{HEAD ~ The other two articulated joints} of {TAIL ~ blade} 2 follow circular orbits around axle 4, since these are kept at a constant distance from axle 4, which is equal to the length of a blade arm 3 
{ HEAD ~ The other two articulated joints } of { TAIL ~ blade } 2 follow circular orbits around axle 4 , since these are kept at a constant distance from axle 4 , which is equal to the length of a blade arm 3
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL 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 OTH OTH OTH OTH OTH OTH OTH OTH