window.onload = function() {

  var scope1 = new paper.PaperScope();

  var scope2 = new paper.PaperScope();

  //

  scope1.setup(document.getElementById('canvas1'));

  scope2.setup(document.getElementById('canvas2'));

  // ACTIVATE SCOPE # 1

  scope1.activate()

  var path = new paper.Path.Circle(paper.view.center, 10);

  path.fillColor = 'red';

  // ACTIVATE SCOPE # 2

  scope2.activate()

  var path = new paper.Path.Rectangle([

    paper.view.center.x-10, 

    paper.view.center.y-10

  ], 20);

  path.fillColor = 'blue';

}