int x,y,dx,dy;
float distance;

void setup(){

  size(300,300);
  noStroke();

}

void loop(){

  for(y= 0; y<300 ; y +=20){
    for(x=0 ; x<300; x +=20){
    
        // ----------kyori hakaru------------
      dx = mouseX - x;
      dy = mouseY - y;
      distance= sqrt(dx*dx+dy*dy);

      fill(distance-20,dx+10,dy+50);
      rect(dx,dy,distance,distance);
    }
  }
}