Black Hall

/**
* Black Hall
*
* @author aa_debdeb
* @ 2015/08/30
*/

void setup(){
  
  size(500, 500);
  noStroke();
  smooth();
  background(255);
  
  float hallSize = 250;
  float gradiationWidth = 200;

  for(int i = 0; i <= 255; i++){
    fill(255 - i);
    float arcWidth =  hallSize + gradiationWidth * ((255.0 - i) / 255.0);
    arc(width / 2, height / 2, arcWidth, arcWidth, 0, 2*PI);
  }  
  
}