A canvas shadow createPattern example

function canvasReady() {
  draw(document.getElementById('canvas').getContext('2d'));
}
function draw(ctx) {
    ctx.translate(-10, 5);
    ctx.scale(1.2, 0.8);
    ctx.rotate(5 * Math.PI / 180);

  // create new image object to use as pattern
  var img = new Image();
  img.onload = function(){
    // create pattern
    var ptrn = ctx.createPattern(img,'repeat');
    ctx.shadowBlur = 15;
    ctx.shadowOffsetX = 10;
    ctx.shadowOffsetY = 10;
    ctx.shadowColor = "gray";
    ctx.beginPath();
    ctx.strokeStyle = ptrn;
    ctx.fillStyle = ptrn;
    ctx.lineWidth = 6;
    ctx.strokeRect(10,10,40,40);
    ctx.strokeRect(30,30,40,40);
    ctx.fillRect(50,50,40,40);
    ctx.fillRect(70,70,40,40);

    // prevent IE6 memory leak
    img = null;
  }
  img.src = '../img/wallpaper.png';
}