​

function setup() {

  createCanvas(600, 400);

}

​

function draw() {

  background("DodgerBlue");

  fill("white"); 

  noStroke(); 

  var freq = map(mouseX, 0, width, 1,10); 

  textSize(20);

  textAlign(CENTER);

  text("freq = " + nf(freq,1,2), width/2,30);

  text("t = freq * millis()", 200, 300); 

  text("t += freq * dt", 400, 300); 

  var m = freq * millis()/1000.0;

  var ehA = map(sin(m), -1,1, 90,130);

  ellipse(200,200,150,ehA); 

  var dt = 0.016666; // 1/60 sec 

  t += freq * dt; 

  var ehB = map(sin(t), -1,1, 90,130);

  ellipse(400,200,150,ehB); 

}