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                <div id="myApp"></div>


                body {
  margin : 0;

.surface {
  background : red;
  line-height: 100px;
  text-align: center;


                var Surface = Samsara.DOM.Surface;
var Context = Samsara.DOM.Context;
var Transitionable = Samsara.Core.Transitionable;
var Transform = Samsara.Core.Transform;
var Accumulator = Samsara.Streams.Accumulator;
var Differential = Samsara.Streams.Differential;
var MouseInput = Samsara.Inputs.MouseInput;

var position = new Accumulator([0,0]);
var mouse = new MouseInput();
var spring = new Transitionable();

// Convert transitionable values to deltas
var springDelta = new Differential();

// Total Position is the sum of mouse and spring deltas

var surface = new Surface({
  content: 'drag me',
	size: [100, 100],
  origin : [.5,.5],
  classes : ['surface']


// On `end` set the spring to be at the current position and animate back to [0,0]
// provide the transition the current velocity of the drag
mouse.on('end', function (data) {
  if (spring.isActive()) spring.halt();
	spring.set([0,0], {
    curve: 'spring', 
    damping: .7, 
    period: 80, 
    velocity : data.velocity

// Map the position to a translation `Transform`
var transform = (value) {
	return Transform.translate(value);

var context = new Context();

context.add({transform : transform, align : [.5,.5]}).add(surface);