Moiré 2

color black = #000000;
color white = #f1f1f1;

void setup() {
  size(800, 600, P2D);
  noFill();
  strokeWeight(3);
  stroke(black);
  rectMode(CENTER);
}

void draw() {  
  background(white);

  for (int i = 0; i < 37; i++) {
    rect(width/2, height/2, i * 15, i*15);
  } 
    
  for (int i = 0; i < 37; i++) {
    rect(mouseX,mouseY, i * 15, i*15);
  } 
}