let x2; let y2;

let x3; let y3;

let x4; let y4;

​

let a1; let b1;

let a2; let b2;

let a3; let b3;

let a4; let b4;

​

​

function setup() {

  createCanvas(800, 800);

   x1 = width / 2; y1 = height / 2;

   x2 = width / 2; y2 = height / 2;

   x3 = width / 2; y3 = height / 2;

   x4 = width / 2; y4 = height / 2;

   a1 = width*0; b1 = height*0;

   a2 = width;   b2 = height*0;

   a3 = width*0; b3 = height;

   a4 = width;   b4 = height;

}

​

function draw() {

  background(10);

  noStroke();

  circle(x1, y1, 80);

  circle(x2, y2, 80);

  circle(x3, y3, 80);

​

  circle(x4, y4, 80);

  x1 +=10;

  x2 -=1;

  y3 +=1;

  y4 -=1;

  circle(a1, b1, 80);

  circle(a2, b2, 80);

  circle(a3, b3, 80);

​

  circle(a4, b4, 80);

  a1 += 1; 

  b1 += 1; 

  a2 -= 1;

  b2 += 1;

  a3 += 1;

  b3 -= 1;

  a4 -= 1;

  b4 -= 1;

}