rotations.js

// This example requires you to add TweenLite.js and Easepack.js to your HTML file.

var r = new Rune({
  container: "#canvas",
  width: 800,
  height: 600
});

function drawTile(x, y) {

  var down = r.random(1) > 0.5;
  var rot = down ? 90 : 0;

  // Draw something
  r.rect(x, y, 50, 50);
  r.line(x + 25, y, x + 25, y + 25).rotate(rot, x + 25, y + 25);
  r.line(x + 25, y + 25, x + 50, y + 25).rotate(rot, x + 25, y + 25);

  // pick a direction
  if(x < r.width && y < r.height) {
    if(down) {
      drawTile(x, y + 50, 0);
    }
    else {
      drawTile(x + 50, y, 0);
    }
  }
}

drawTile(0, 0);

r.play();