var width = window.innerWidth;

        var height = window.innerHeight;

        var renderer = new THREE.WebGLRenderer();

        document.body.appendChild(renderer.domElement);

        renderer.setSize(width,height);

        var scene = new THREE.Scene();

        var camera = new THREE.OrthographicCamera( width / - 2, width / 2, height / 2, height / - 2, -10, 10 );

​

​

        var particles = [];

​

        var particle = function(position) 

        {

          this.A = 0;

          this.p = 0;

          this.radius = 10;

          this.velocity = new THREE.Vector3();

          this.mesh = new THREE.Mesh(new THREE.CircleGeometry(this.radius, 32), new THREE.MeshBasicMaterial({color: 0x0000ff}));

          if(position)

          this.mesh.position.set(position.x,position.y,0);

          scene.add(this.mesh);

          particles.push(this);

        };

​

​

        var step = function() 

        {

            var restitution = 0.5;

​

            for(var i=0; i<particles.length; i++) 

            {

                var lowerLimit = -height/2;

                var upperLimit = height/2;

                var leftLimit = -width/2;

                var rightLimit = width/2;

                var pi = particles[i];

                if(pi.mesh.position.y < lowerLimit) 

                {

                    pi.velocity.y = -pi.velocity.y*restitution;

                    pi.mesh.position.y = lowerLimit;

                }

                if(pi.mesh.position.y > upperLimit) 

                {

                    pi.velocity.y = -pi.velocity.y*restitution;

                    pi.mesh.position.y = upperLimit;

                }

                if(pi.mesh.position.x < leftLimit) 

                {

                    pi.velocity.x = -pi.velocity.x*restitution;

                    pi.mesh.position.x = leftLimit;

                }               

                if(pi.mesh.position.x > rightLimit) 

                {

                    pi.velocity.x = -pi.velocity.x*restitution;

                    pi.mesh.position.x = rightLimit;

                }                                                       

            }

            for(var i=0; i<particles.length; i++) 

            {

                var pi = particles[i];

                for(var j=0; j<i+1; j++) 

                {

                    var pj = particles[j];

​

                    var pimpj = pi.mesh.position.clone().sub(pj.mesh.position); 

                    var pjmpi = pj.mesh.position.clone().sub(pi.mesh.position); 

                    if(pimpj.length() < 20 && pimpj.length() != 0) 

                    {

​

​

                        pi.velocity = pi.velocity.reflect(pjmpi.clone().normalize()).multiplyScalar(restitution); 

                        pj.velocity = pj.velocity.reflect(pimpj.clone().normalize()).multiplyScalar(restitution);

​

                        var pip = pi.velocity.clone().normalize().multiplyScalar(20-pimpj.length());

                        var pjp = pj.velocity.clone().normalize().multiplyScalar(20-pimpj.length());

                        pi.mesh.position.add(pip);

                        pj.mesh.position.add(pjp);

                    }

                } 

​

​

            }

            for(var i=0; i<particles.length; i++) 

            {

                var pi = particles[i];

                pi.velocity.add(new THREE.Vector3(0,-0.001,0));

                pi.mesh.position.add(pi.velocity);

​

            }

        };

        var render = function() 

        {

            renderer.render(scene,camera);        

        };

        var spawnParticles = function() 

        {

            var rows = 10, columns = 10, space = 50;

            var offsetX = -width/2+500;

            var offsetY = -height/2+100;

            for(var i=0; i<rows; i++) 

            {

                for(var j=0; j<columns; j++)

                {

                var p = new particle(new THREE.Vector3(i*space+offsetX,j*space+offsetY,0));

                p.velocity.set(Math.random()-0.5*2,Math.random()-0.5*2,0);

                }

            }

​

        };

        spawnParticles();

        var loop = setInterval(function() {

            render();

            step();

        },10);