interface Blinkable extends Runnable, Drawable {
  float MAXRATE = 10 * 0.001f;  // maximum blinking rate is 10 flashes per second
  float MINRATE = 0.1f * 0.001f; // minimum blinking rate is 1 flash per 10 seconds 
  void  startBlinking();
  void  stopBlinking();
  void  setBlinkingRate(float r);
  float getBlinkingRate();  
}