var delta = 0.05;

​

function setup() {

  createCanvas(400, 400);

  //frameRate(20);

  rectMode(CENTER);

}

​

function rotating_square(x){

  push();

  var ang = map(x, 0, 20, 0, TWO_PI);

  var cos_a = cos(ang);

  var sin_a = sin(ang);

  translate(50,50);

  applyMatrix(cos_a, sin_a, -sin_a, cos_a, 0, 0);

  rect(0,0,50,50);

  pop();

}

​

​

function shrinking_square(x){

  push();

  var step = map(x%50,0,50,-200,200);

  step = -(step*step)*(1/50);

​

  translate(150,150);

  applyMatrix(1 / step, 0, 0, 1 / step, 0, 0);

  rect(0,0,50,50);

  pop();

}

​

​

function draw() {

  background(220);

  rotating_square(time);

  shrinking_square(time);

  time+=delta;

}