at least a part of {TAIL ~ the first element} is closer to the front surface than the second element is to {HEAD ~ the front surface} 
at least a part of { TAIL ~ the first element } is closer to the front surface than the second element is to { HEAD ~ the front surface }
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD