In one embodiment, the spacer includes {HEAD ~ at least one cushioning segment} defining {TAIL ~ a gap} for providing the separation 
defining
In one embodiment , the spacer includes { HEAD ~ at least one cushioning segment } defining { TAIL ~ a gap } for providing the separation
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