The support 2 wherein the envelope of {TAIL ~ one support} can be stacked on the envelope of {HEAD ~ another support} and used in multiple 
The support 2 wherein the envelope of { TAIL ~ one support } can be stacked on the envelope of { HEAD ~ another support } and used in multiple
OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH