sinterface WidthAndHeight {
  int getWidth aka w aka width();
  int getHeight aka h aka height();
  
  public default Rect bounds() { ret rect(0, 0, getWidth(), getHeight()); }
  
  default int area() { ret toInt(areaAsLong()); }
  default long areaAsLong() { ret longMul(w(), h()); }
}

Began life as a copy of #1015472