Each of the end walls has a first end, a second end and {HEAD ~ a free side} from which {TAIL ~ a horizontal plate} extends transversely 
Each of the end walls has a first end , a second end and { HEAD ~ a free side } from which { TAIL ~ a horizontal plate } extends transversely
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH