In {TAIL ~ some embodiments}, grooves 350 and 352 are annular threaded grooves and flexible electrical connectors 322 and 324 include {HEAD ~ threads} such that the connectors 322 and 324 can be screwed into grooves 350 and 352 
In { TAIL ~ some embodiments } , grooves 350 and 352 are annular threaded grooves and flexible electrical connectors 322 and 324 include { HEAD ~ threads } such that the connectors 322 and 324 can be screwed into grooves 350 and 352
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH