At least two frame engaging {HEAD ~ members} of the frame support structure are moved to position the side members of the frame in {TAIL ~ a desired configuration} 
At least two frame engaging { HEAD ~ members } of the frame support structure are moved to position the side members of the frame in { TAIL ~ a desired configuration }
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 OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL