let b = 300

​

function setup() {

  createCanvas(400, 400);

}

​

function draw() {

  background(200);

​

  // Draw them

  ellipse(a, height / 2, 50, 50);

  ellipse(b, height / 2, 50, 50);

  let m = 1/(a-b);

  // print(m)

  b += m*100

}

​