code: public void add(double x, double y) {
      data.add(x);
      data.add(y);
      minx = Math.min(minx, x);
      maxx = Math.max(maxx, x);
      miny = Math.min(miny, y);
      maxy = Math.max(maxy, y);
    }
docs: Add a coordinate pair, but don't simplify
  
  @param x X coordinate
  @param y Y coordinate