{TAIL ~ The apparatus} has a hollow body , with an inflow and an outflow for {HEAD ~ the fluid}  
{ TAIL ~ The apparatus } has a hollow body , with an inflow and an outflow for { HEAD ~ the fluid }
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH