    TempleOS has a class for 3 dimensional points consisting of F64s.  HolyC is not
    C++ -- it does not support passing or returning values from functions which are
    not 64-bits, therefore, it can't be implemented with operator overloading.
    Making all function args and returns 64-bit is a core prinicple of TempleOS.

    As a courtesy, most of the CD3 functions return the addr of the destination
    vect, so you can nestle calls.  They do not alloc new space for the destination
    vect.