GraphicsDeviceManager graphics;
        VertexPositionColor[] verts;
        BasicEffect ef;
        public Game1()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";
        }
        protected override void Initialize()
        {
            base.Initialize();
        }
        protected override void LoadContent()
        {
            verts = new VertexPositionColor[4];
            verts[0] = new VertexPositionColor(new Vector3(0, 0, 1), Color.Red);
            verts[1] = new VertexPositionColor(new Vector3(0, 1, 0), Color.Red);
            verts[2] = new VertexPositionColor(new Vector3(1, 0, 0), Color.Red);
            verts[3] = new VertexPositionColor(new Vector3(1, 1, 1), Color.Red);
            short[] userindex = { 0, 1, 1, 2, 2, 3, 3, 0 };
            VertexBuffer vb = new VertexBuffer(GraphicsDevice, typeof(VertexPositionColor), verts.Length, BufferUsage.None);
            vb.SetData(verts);
            GraphicsDevice.SetVertexBuffer(vb);
            IndexBuffer indexbuffer = new IndexBuffer(GraphicsDevice, IndexElementSize.SixteenBits, userindex.Length, BufferUsage.None);
            indexbuffer.SetData(userindex);
            GraphicsDevice.Indices = indexbuffer;
            ef = new BasicEffect(GraphicsDevice);
            ef.World = Matrix.Identity;
            ef.View = Matrix.CreateLookAt(new Vector3(0, 0, 4), new Vector3(0, 0, -1), Vector3.Up);
            ef.Projection = Matrix.CreatePerspective((float)GraphicsDevice.Viewport.Width / GraphicsDevice.Viewport.Height, 1, 1.125f, 10);
            ef.VertexColorEnabled = true;
            foreach (EffectPass pass in ef.CurrentTechnique.Passes)
                pass.Apply();
        }
        protected override void UnloadContent()
        {
            
        }
        protected override void Update(GameTime gameTime)
        {
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();
            base.Update(gameTime);
        }
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.CornflowerBlue);
            GraphicsDevice.DrawIndexedPrimitives(PrimitiveType.LineList, 0, 0, verts.Length, 0, 4);
            base.Draw(gameTime);
        }