createCanvas(400, 400);

}

​

function draw() {

  background(200);

​

  var period = 1000; // milliseconds

  var percent = (millis()%period)/period;

  var xA = 0; 

  var xB = width;

  var px = lerp(xA, xB, percent);

  ellipse(px, 200, 40, 40);

}