                      display.width()/2-i, display.height()/2+i,
                      display.width()/2+i, display.height()/2+i, WHITE);
     display.display();
+    delay(1);
   }
 }
 

  display.clearDisplay();
  display.drawBitmap(30, 16,  logo16_glcd_bmp, 16, 16, 1);
  display.display();

  // invert the display
  display.invertDisplay(true);

  for (int16_t i=0; i<display.height(); i+=4) {
    display.drawLine(display.width()-1, 0, 0, i, WHITE);
    display.display();
    delay(1);
  }
  for (int16_t i=0; i<display.width(); i+=4) {
    display.drawLine(display.width()-1, 0, i, display.height()-1, WHITE); 
    display.display();
    delay(1);
  }
  delay(250);
}
