code: public void setAllCorners(CornerTreatment cornerTreatment) {
          topLeftCorner = cornerTreatment.clone();
          topRightCorner = cornerTreatment.clone();
          bottomRightCorner = cornerTreatment.clone();
          bottomLeftCorner = cornerTreatment.clone();
      }
docs: Sets all corner treatments.
  
  @param cornerTreatment the corner treatment to use for all four corners.