As shown in FIG 7a and further in FIG 8a, {TAIL ~ this action} stretches the center section of the fabric between {HEAD ~ elements} 48, 48, increasing the open space, i.e. porosity, of the fabric 
As shown in FIG 7a and further in FIG 8a , { TAIL ~ this action } stretches the center section of the fabric between { HEAD ~ elements } 48 , 48 , increasing the open space , i.e. porosity , of the fabric
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH