{HEAD ~ The output unit} 150 is connected to {TAIL ~ a display unit} 151 to display the flow Q and to a memory unit 152 to store the flow data 
{ HEAD ~ The output unit } 150 is connected to { TAIL ~ a display unit } 151 to display the flow Q and to a memory unit 152 to store the flow data
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH