 at least certain of said adapter blocks have a length dimension equal to the distance between hub axes of two connector elements when joined by a rod element having a length Lx, where “{HEAD ~ x}” is {TAIL ~ a whole number} from 1 to n 
is
at least certain of said adapter blocks have a length dimension equal to the distance between hub axes of two connector elements when joined by a rod element having a length Lx , where “ { HEAD ~ x } ” is { TAIL ~ a whole number } from 1 to n
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH