let theta = 0;

let theta2 = 0;

function setup() {

  createCanvas(1000, 1000);

  angleMode(RADIANS);

}

​

function draw() {

  background(220);

  translate(width/2,height/2);

  let _x = 250 * cos(theta);

  let _y = 250 * sin(theta);

  let _x2 = 500 * cos(theta2);

  let _y2 = 500 * sin(theta2);

  for (let i = 0; i < 250; i += 10) {

    noFill();

    stroke("purple");

    strokeWeight(4);

    ellipse(0, 0, i, i);

    stroke("red");

    strokeWeight(3);

    ellipse(_x, _y, 240-i, 250-i);

    stroke("blue");

    strokeWeight(3);

    ellipse(_x2, _y, 240-i, 250-i);

  }

  theta += TWO_PI/256;

  theta2 -= TWO_PI/512;

  // if (x > width) x = 0

  // else x += 3;

}