code: public static ImmutableVector4 copy(Vector4 source) {
  		if (source instanceof ImmutableVector4) return (ImmutableVector4)source;
  		return createVector(source.getX(), source.getY(), source.getZ(), source.getH());
  	}
docs: Returns an immutable vector with the same values as the argument.
  
  @param source the vector containing the data for the new immutable vector
  @return an immutable vector containing the same elements as {@code source}
  @throws NullPointerException if {@code source} is {@code null}