public Pnt extend(double... coords){
  double[] result=new double[coordinates.length + coords.length];
  System.arraycopy(coordinates,0,result,0,coordinates.length);
  System.arraycopy(coords,0,result,coordinates.length,coords.length);
  return new Pnt(result);
}

public Pnt extend ( double ... coords ) { double [ ] result = new double [ coordinates . length + coords . length ] ; System . arraycopy ( coordinates , 0 , result , 0 , coordinates . length ) ; System . arraycopy ( coords , 0 , result , coordinates . length , coords . length ) ; return new Pnt ( result ) ; }
create a new pnt by adding additional coordinates to this pnt .
