concept G22MaskSize is WidthAndHeight {
  int width = g22defaultMaskSideLength(), height = g22defaultMaskSideLength();
  
  public int getWidth() { ret width; }
  public int getHeight() { ret height; }
  
  *() {}
  *(int widthHeight) {
    width = height = widthHeight;
  }
  
  bool square() { ret width == height; }
  
  toString {
    ret spaceCombine("Mask Size",
      square()
        ? width + "²"
        : width + "*" + height); }
}