public class Game1 : Microsoft.Xna.Framework.Game

    {

        GraphicsDeviceManager graphics;

        SpriteBatch spriteBatch;

        private Texture2D simpleBackground;

        private Texture2D wheelTexture;

        private Texture2D bodyTexture;

        private World physicsWorld;

        private Body FrontWheelBody;

        private Body BackWheelBody;

        private Body boardBody;

        public Game1()

        {

            graphics = new GraphicsDeviceManager(this);

            Content.RootDirectory = "Content";

            // Frame rate is 30 fps by default for Windows Phone.

            TargetElapsedTime = TimeSpan.FromTicks(333333);

            graphics.IsFullScreen = true;

            graphics.SupportedOrientations = DisplayOrientation.LandscapeRight;

            graphics.ApplyChanges();

        }

        /// <summary>

        /// Allows the game to perform any initialization it needs to before starting to run.

        /// This is where it can query for any required services and load any non-graphic

        /// related content.  Calling base.Initialize will enumerate through any components

        /// and initialize them as well.

        /// </summary>

        protected override void Initialize()

        {

            physicsWorld = new World(new Vector2(0,10),true);

            base.Initialize();

        }

        /// <summary>

        /// LoadContent will be called once per game and is the place to load

        /// all of your content.

        /// </summary>

        protected override void LoadContent()

        {

            // Create a new SpriteBatch, which can be used to draw textures.

            spriteBatch = new SpriteBatch(GraphicsDevice);

            simpleBackground = Content.Load<Texture2D>("carbackground");

            wheelTexture = Content.Load<Texture2D>("wheelCopy");

            bodyTexture = Content.Load<Texture2D>("board");

            CreateGround();

            CreateCar();

        }

        private RevoluteJoint frontWheelJoint;

        private RevoluteJoint backWheelJoint;

        private void CreateCar()

        {

            var bodyDef = new BodyDef {type = BodyType.Dynamic};

            var wheelShape = new CircleShape {_radius = wheelTexture.Width/2f*0.01f};

            var wheelFixture = new FixtureDef {shape = wheelShape, density =1f,restitution=.2f,friction=.5f};

            FrontWheelBody = physicsWorld.CreateBody(bodyDef);

            BackWheelBody = physicsWorld.CreateBody(bodyDef);

            FrontWheelBody.Position = new Vector2(2.9f, 1.41f);

            BackWheelBody.Position = new Vector2(3.9f, 1.41f);

            FrontWheelBody.CreateFixture(wheelFixture);

            BackWheelBody.CreateFixture(wheelFixture);

            boardBody = physicsWorld.CreateBody(bodyDef);

            var bodyShape = new PolygonShape();

            bodyShape.SetAsBox(bodyTexture.Width/2f*0.01f, bodyTexture.Height/2f*0.01f);

            var bodyFix = new FixtureDef() {friction = 1.0f, shape = bodyShape, density = 1.0f, restitution = .1f};

            boardBody.Position = new Vector2(3.4f, 1.41f);

            boardBody.CreateFixture(bodyFix);

            var rj = new RevoluteJointDef();

            rj.Initialize(boardBody, FrontWheelBody, FrontWheelBody.GetWorldCenter());

            rj.enableMotor = true;

            rj.maxMotorTorque = .1f;

            var rj2 = new RevoluteJointDef();

            rj2.Initialize(boardBody, BackWheelBody, BackWheelBody.GetWorldCenter());

            rj2.enableMotor = true;

            rj2.maxMotorTorque = .1f;

            frontWheelJoint = (RevoluteJoint) physicsWorld.CreateJoint(rj);

            backWheelJoint = (RevoluteJoint)physicsWorld.CreateJoint(rj2);

        }

        private void CreateGround()

        {

            var bodyDef = new BodyDef();

            bodyDef.type = BodyType.Static;

            var bodyShape = new PolygonShape();

            var bodyFix = new FixtureDef();

            bodyFix.density = 0.0f;

            bodyFix.friction = 1.0f;

            var topLeft = physicsWorld.CreateBody(bodyDef);

            bodyShape.SetAsEdge(new Vector2(0, 4.0f), new Vector2(2.0f, 4.0f));

            bodyFix.shape = bodyShape;

            topLeft.CreateFixture(bodyFix);

            var sideLeft = physicsWorld.CreateBody(bodyDef);

            bodyShape.SetAsEdge(new Vector2(2.0f,4.0f), new Vector2(2.0f,4.8f));

            bodyFix.shape = bodyShape;

            sideLeft.CreateFixture(bodyFix);

            var ground = physicsWorld.CreateBody(bodyDef);

            bodyShape.SetAsEdge(new Vector2(2.0f,4.6f), new Vector2(6.0f,4.6f));

            bodyFix.shape = bodyShape;

            ground.CreateFixture(bodyFix);

            var topRight = physicsWorld.CreateBody(bodyDef);

            bodyShape.SetAsEdge(new Vector2(6.0f,4.0f), new Vector2(6.0f,4.8f));

            bodyFix.shape = bodyShape;

            topRight.CreateFixture(bodyFix);

            var sideRight = physicsWorld.CreateBody(bodyDef);

            bodyShape.SetAsEdge(new Vector2(6.0f,4.0f), new Vector2(8.0f,4.0f));

            bodyFix.shape = bodyShape;

            sideRight.CreateFixture(bodyFix);

        }

        protected override void Update(GameTime gameTime)

        {

            // Allows the game to exit

            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)

                this.Exit();

            physicsWorld.Step(1/30f, 10, 10);

            HandleKeyDown();

            base.Update(gameTime);

        }

        private KeyboardState prevKeyboardState;

        private void HandleKeyDown()

        {

            var state = Keyboard.GetState();

            if (state.IsKeyDown(Keys.Left) && prevKeyboardState.IsKeyDown(Keys.Left))

            {

                frontWheelJoint.SetMotorSpeed(-10f);

                backWheelJoint.SetMotorSpeed(-10f);

            }

            if (state.IsKeyDown(Keys.Right) && prevKeyboardState.IsKeyDown(Keys.Right))

            {

                frontWheelJoint.SetMotorSpeed(10f);

                backWheelJoint.SetMotorSpeed(10f);

            }

            prevKeyboardState = state;

        }

        protected override void Draw(GameTime gameTime)

        {

            GraphicsDevice.Clear(Color.CornflowerBlue);

            spriteBatch.Begin();

            spriteBatch.Draw(simpleBackground, Vector2.Zero, Color.White);

            spriteBatch.Draw(wheelTexture, FrontWheelBody.Position/0.01f, null, Color.White, FrontWheelBody.Rotation,

                             new Vector2(wheelTexture.Width/2f, wheelTexture.Height/2f), 1, SpriteEffects.None, 0);

            spriteBatch.Draw(wheelTexture, BackWheelBody.Position / 0.01f, null, Color.White, BackWheelBody.Rotation,

                             new Vector2(wheelTexture.Width / 2f, wheelTexture.Height / 2f), 1, SpriteEffects.None, 0);

            spriteBatch.Draw(bodyTexture, boardBody.Position/0.01f, null, Color.White, boardBody.Rotation,

                             new Vector2(bodyTexture.Width/2f, bodyTexture.Height/2f), 1, SpriteEffects.None, 0);

            spriteBatch.End();

            base.Draw(gameTime);

        }