// Drag (click and hold) your mouse across the 
// image to change the value of the rectangle 
 
int value = 0; 
 
void loop() { 
  fill(value); 
  rect(25, 25, 50, 50); 
} 
 
void mouseDragged() 
{ 
  value = value + 5; 
  if (value > 255) { 
    value = 0; 
  } 
}