The second ends of the elongated flexible elements are connected respectively to {HEAD ~ the first and second surfaces} at {TAIL ~ one end} of the surface, wherein the fexible elements are operable to be wound or unwound on the respective surfaces as the member rotates about the axis 
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The second ends of the elongated flexible elements are connected respectively to { HEAD ~ the first and second surfaces } at { TAIL ~ one end } of the surface , wherein the fexible elements are operable to be wound or unwound on the respective surfaces as the member rotates about the axis
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD 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 OTH OTH OTH