Disposed in each channel 100 is {HEAD ~ a generally elongated coil spring} 102 that is anchored at {TAIL ~ one point} to a point of the frame structure forming a part of the support structure 10, and wherein screens 22 and 24 and top 50 are connected at predetermined points to each of the springs 102 
is anchored at
Disposed in each channel 100 is { HEAD ~ a generally elongated coil spring } 102 that is anchored at { TAIL ~ one point } to a point of the frame structure forming a part of the support structure 10 , and wherein screens 22 and 24 and top 50 are connected at predetermined points to each of the springs 102
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH