let centerY = 10;

​

function setup() {

  createCanvas(400, 400);

  frameRate(10);

}

​

function draw() {

  noFill();

  translate(centerX, centerY);

  rotate(radians(random(-10, 10)));

  rect(0, 0, 10, 10);

  centerX = centerX + 20;

  if (centerX > width) {

    centerX = 10;

    centerY = centerY + 20;

  }

}