int x;
int y;
int dx,dy;
float distance;
void setup(){
  size(300,300);
   rectMode(CENTER_DIAMETER);
  /*
  noStroke();
*/}

void loop(){

  for(y=0;y<300;y+=30){
    for(x=0;x<300;x+=50){

      dx=mouseX-x;
      dy=mouseY-y;
      distance=sqrt(dx*dx+dy*dy);
      strokeWeight(10);
      fill(255-distance,distance,distance);
      rect(x,y,distance*2,distance);
      fill(255-distance,255-distance,x);
      ellipse(y,x,distance-50,distance-50);

    }
  }

}