text: var Example = Example || {};
  
  Example.chains = function() {
      var Engine = Matter.Engine,
          Render = Matter.Render,
          Runner = Matter.Runner,
          Body = Matter.Body,
          Composite = Matter.Composite,
          Composites = Matter.Composites,
          Constraint = Matter.Constraint,
          MouseConstraint = Matter.MouseConstraint,
          Mouse = Matter.Mouse,
          World = Matter.World,
          Bodies = Matter.Bodies;
  
      // create engine
      var engine = Engine.create(),
          world = engine.world;
  
      // create renderer
      var render = Render.create({
          element: document.body,
          engine: engine,
          options: {
              width: Math.min(document.documentElement.clientWidth, 800),
              height: Math.min(document.documentElement.clientHeight, 600),
              showAngleIndicator: true,
              showCollisions: true,
              showVelocity: true
          }
      });
  
      Render.run(render);
  
      // create runner
      var runner = Runner.create();
      Runner.run(runner, engine);
  
      // add bodies
      var group = Body.nextGroup(true);
          
      var ropeA = Composites.stack(200, 100, 4, 2, 10, 10, function(x, y) {
          return Bodies.rectangle(x, y, 50, 20, { collisionFilter: { group: group } });
      });
      
      Composites.chain(ropeA, 0.5, 0, -0.5, 0, { stiffness: 0.8, length: 2 });
      Composite.add(ropeA, Constraint.create({ 
          bodyB: ropeA.bodies[0],
          pointB: { x: -25, y: 0 },
          pointA: { x: 200, y: 100 },
          stiffness: 0.5
      }));
      
      World.add(world, ropeA);
      
      group = Body.nextGroup(true);
      
      var ropeB = Composites.stack(500, 100, 5, 2, 10, 10, function(x, y) {
          return Bodies.circle(x, y, 20, { collisionFilter: { group: group } });
      });
      
      Composites.chain(ropeB, 0.5, 0, -0.5, 0, { stiffness: 0.8, length: 2 });
      Composite.add(ropeB, Constraint.create({ 
          bodyB: ropeB.bodies[0],
          pointB: { x: -20, y: 0 },
          pointA: { x: 500, y: 100 },
          stiffness: 0.5
      }));
      
      World.add(world, ropeB);
  
      // add mouse control
      var mouse = Mouse.create(render.canvas),
          mouseConstraint = MouseConstraint.create(engine, {
              mouse: mouse,
              constraint: {
                  stiffness: 0.2,
                  render: {
                      visible: false
                  }
              }
          });
  
      World.add(world, mouseConstraint);
  
      // keep the mouse in sync with rendering
      render.mouse = mouse;
  
      // fit the render viewport to the scene
      Render.lookAt(render, {
          min: { x: 0, y: 0 },
          max: { x: 700, y: 600 }
      });
  
      // context for MatterTools.Demo
      return {
          engine: engine,
          runner: runner,
          render: render,
          canvas: render.canvas,
          stop: function() {
              Matter.Render.stop(render);
              Matter.Runner.stop(runner);
          }
      };
  };