Then, the oil having flowed into {HEAD ~ the horizontal path} 36 flows up along {TAIL ~ the vertical path} 32 
Then , the oil having flowed into { HEAD ~ the horizontal path } 36 flows up along { TAIL ~ the vertical path } 32
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH