The base 12 has {TAIL ~ a top surface} 16 and {HEAD ~ a bottom surface} 18 opposite thereto 
The base 12 has { TAIL ~ a top surface } 16 and { HEAD ~ a bottom surface } 18 opposite thereto
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH