var amp = 60;

​

xPos = 0;

​

function setup() {

  createCanvas(600, 300);

  fill(255);

  noStroke();

  //background(244, 132, 140);

}

​

​

function draw() {

  background(244, 132, 140);

  theta += 0.02;

  var diam = 100 + sin(theta) * amp;

​

  ellipse(width/2, height/2, diam);

}