code: public static ImmutableMatrix2 copy(Matrix2 source) {
  		if (source instanceof ImmutableMatrix2) return (ImmutableMatrix2)source;
  		return new ImmutableMatrix2(source);
  	}
docs: Returns an immutable matrix with the same values as the argument.
  
  @param source the matrix containing the data for the new immutable matrix
  @return an immutable matrix containing the same elements as {@code source}
  @throws NullPointerException if {@code source} is {@code null}