{HEAD ~ a first electrode} having a first pair of bipolar contacts attached to {TAIL ~ the expandable balloon}; and 
{ HEAD ~ a first electrode } having a first pair of bipolar contacts attached to { TAIL ~ the expandable balloon } ; and
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH