Alternatively, one or more edges of the routing area may coincide with one or more edges of {HEAD ~ chips} or {TAIL ~ circuit elements} 
Alternatively , one or more edges of the routing area may coincide with one or more edges of { HEAD ~ chips } or { TAIL ~ circuit elements }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL