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HTML 

              
                <canvas id="canv"></canvas>
<p>Cocoon</p>
<!--
Titillating Tip:
After connecting a few, wait a second for them  to settle down, then add another from further away to see how cocoon movement / responds to force based on distance && velocity.
!-->
!

CSS 

              
                @import url(https://fonts.googleapis.com/css?family=Titillium+Web:700);
body{
  width:100%; 
  overflow:auto;
  user-select:none;
}
p{
  top:2em;
  width:100%; 
  text-align:center;
  position:absolute;
  color:  hsla(175, 65%, 5%, 1);
  font-size:5em;
  font-family: 'Titillium Web', sans-serif;
  letter-spacing:40px;
}
canvas{
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  height: 100%;
}
!

JS 

              
                var w = window.innerWidth;
var h = window.innerHeight;
var spr_d = (w > h) ?h/3 : w/3;
var $;
var FPS = 30;
var num = 5;
var grav = 0;
var fric = 0.001;
var spr;
var node2;
var parts = [];
var springs = []; 
var count = 0;
    
window.onload = function() {
  node2 = new Node2();
	c = document.getElementById('canv');
	c.width = w;
	c.height = h;
	$ = c.getContext('2d');
  $.fillStyle = 'hsla(175, 5%, 95%, 1)';
  $.fillRect(0,0,w,h);
  $.fill();
  $.strokeStyle = 'hsla(175, 15%, 5%, .65)';
  $.lineWidth = 1;
 
    var p = new Part();
    p.setup({
        x : w/2,
        y : h/2,
        len : 0,
        ang : 0,
        $$: $,
        rad : 10,
        fric : fric,
        frc : {x:0, y:grav},
        color: 'hsla(175, 65%, 5%, 1)',
        fix: true
    });
    parts.push(p);
    
    if(document.addEventListener){
        document.addEventListener('click', add); 
    
    }else if(document.attachEvent){
    }
	setInterval( function(){
        if(parts.length){
            upd();
            window.requestAnimationFrame(draw);
        }
	}, 1000 / FPS );
}
function upd(){
    for(var i = 0; i<parts.length; i++){
        parts[i].reset({x:Math.random()-0.5, y:Math.random()-0.5});
    }
    for(i = 0; i<springs.length; i++){
        springs[i].upd();
    }
    for(i = 0; i<parts.length; i++){
        parts[i].upd();
    }
    
}
function draw(){
   $.fillStyle = 'hsla(175, 5%, 95%, .5)';
   $.fillRect(0,0,w,h);
   $.fill();
    for(var i = 0; i<springs.length; i++){
        springs[i].draw();
    }
    for(i = 0; i<parts.length; i++){
        parts[i].draw();
    }
}
function add(e){
    parts.push(create(e.clientX, e.clientY));
    for(i = parts.length-2; i>=0; i--){
        var spr = new Spring({
            dist : 260,
            springy : 0.01,
            pa : parts[parts.length-1],
            pb : parts[i],
            $$ : $
        });
        springs.push(spr);
        
    }
}

var Node2 = function(_x, _y){
    this.x = _x || 0;
    this.y = _y || 0;
};
Node2.prototype = {
    x : 0,
    y : 0,
    val : function(_x, _y) {
        if(_x) this.x = _x;
        if(_y) this.y = _y;
        return this;
    },
    len: function(_x, _y){
        this.val(_x, _y);
        return Math.sqrt(this.x*this.x+this.y*this.y);
    },
    norm: function(_x, _y){
        this.val(_x, _y);
        var len = this.len();
        return {x:this.x/len, y:this.y/len};
    },
    sum : function(obj1, obj2){
		this.x = obj1.x + obj2.x;
		this.y = obj1.y + obj2.y;
        return {x: this.x, y: this.y};
    },
    diff : function(obj1, obj2){
        this.x = obj1.x - obj2.x;
		this.y = obj1.y - obj2.y;
        return {x: this.x, y: this.y};
    },
	scale : function(obj, scale){
		this.x = obj.x * scale;
		this.y = obj.y * scale;
        return {x: this.x, y: this.y}; 
	}
};

function create(_x, _y){
    var p = new Part();
    p.setup({
        x : _x,
        y : _y,
        len : Math.random()*20,
        ang : Math.random()*360,
        $$: $,
        rad : 10,
        fric : fric,
        frc : {x:0, y:grav},
        color: 'hsla(175, 65%, 5%, .9)'
    });
    return p;
}

var Part = function() {
    this.pos = {x:0, y:0};
    this.frc = {x:0, y:0};
    this.vel = {x:0, y:0};
    this.rad = 10;
    this.fric = 0.1;
    this.color = 'hsla(175, 65%, 5%, .75)';
    this.fix = false;
};
Part.prototype = {
    $$: null,
    setup: function(obj) {
        this.pos = {x:obj.x, y:obj.y};
        this.rad = obj.rad;
        this.fric = obj.fric;
        this.$$ = obj.$$;
        this.frc = obj.frc;
        var rad = obj.ang * Math.PI / 180;
        var velX = Math.round(Math.cos(rad)*obj.len);
        var velY = Math.round(Math.sin(rad)*obj.len);
        this.vel = { x:velX, y:velY };
        if(obj.color) this.color = obj.color;
        if(obj.fix) this.fix = true;
    },
    upd: function(){
		var _frc = node2.scale(this.vel, this.fric);
        this.frc = node2.diff(this.frc, _frc);
        this.vel = node2.sum(this.vel, this.frc);
        if(!this.fix) {
            this.pos = node2.sum(this.pos, this.vel);
        }
		var cocoon = false;
        if( this.pos.x > w - this.rad) {
            this.pos.x = w - this.rad;
            this.vel.x *= -1;
			cocoon = true;
        } else if( this.pos.x < this.rad ) {
			this.pos.x = this.rad;
            this.vel.x *= -1;
			cocoon = true;
		}
        if( this.pos.y > h - this.rad ) {
            this.pos.y = h - this.rad;
            this.vel.y *= -1;
			cocoon = true;
        } else if( this.pos.y < this.rad ) {
			this.pos.y = this.rad;
            this.vel.y *= -1;
			cocoon = true;
		}
		if( cocoon ) {
			this.vel = node2.scale(this.vel, 0.3);
		}
    },
    draw: function(){
        if(!this.fix){
            this.$$.beginPath();
            this.$$.fillStyle = this.color;
            this.$$.arc(Math.round(this.pos.x), Math.round(this.pos.y), this.rad, 0, Math.PI*2, true);
            this.$$.fill();
            this.$$.beginPath();
            this.$$.fillStyle = 'hsla(58, 95%, 55%, 1)';	
            this.$$.arc(Math.round(this.pos.x), Math.round(this.pos.y), 3, 0, Math.PI*2, true);
            this.$$.fill();
        }
    },
    reset: function(_frc){
        this.frc = _frc;
    },
    addFrc: function(_frc){
        this.frc = node2.sum(this.frc, _frc);
    }
}

var Spring = function(obj){
	this.dist = obj.dist;
	this.springy = obj.springy;
	this.pa = obj.pa;
	this.pb = obj.pb;
	this.$$ = obj.$$;
};
Spring.prototype = {
	upd : function(){
        var diff = node2.diff(this.pa.pos, this.pb.pos);
        var curDis = node2.len(diff.x, diff.y);
        var sprFrc = this.springy * (this.dist - curDis);
        var param = node2.norm(diff.x, diff.y);
        
        this.pa.addFrc({x:param.x*sprFrc, y:param.y*sprFrc});
        this.pb.addFrc({x:-param.x*sprFrc, y:-param.y*sprFrc});
	},
	draw : function() {
        if( !this.pa.fix && !this.pb.fix){
            var diff = node2.diff(this.pa.pos, this.pb.pos);
            var curDis = node2.len(diff.x, diff.y);
            var alpha = 1-curDis/spr_d;
            this.$$.beginPath();
            this.$$.strokeStyle = 'hsla(175, 15%, 5%, ),'+alpha+')';
            this.$$.moveTo(this.pa.pos.x, this.pa.pos.y);
            this.$$.lineTo(this.pb.pos.x, this.pb.pos.y);
            this.$$.stroke();
      }
	}
}
!
999px

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