Демонстрация графики в C#

Просто демонстрация работы графики) В проекте используется таймер и 4 формы)
Форма1: Рисуется случайным образом прямоугольник и эллипс в любой части формы
Форма2: Форма заполняется линиями в случайном порядке, которые имеют разную толщину и цвет. Для заполнения используется таймер
Форма3: Рисует на форме кривую вершина которой находится в точке клика мышки по форме
Форма4: С помощью таймера происходит перемещение круга и прямоугольника на форме.

Форма1:
namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        Random rnd=new Random();
        private int x, y;
        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            g.DrawLine(Pens.Coral, x = rnd.Next(0, 300), y = rnd.Next(0, 300), x = rnd.Next(0, 300), y = rnd.Next(10, 300));
            g.FillEllipse(Brushes.Crimson, x = rnd.Next(10, 300), y = rnd.Next(10, 300), 50, 30);
            g.FillRectangle(Brushes.GreenYellow, x = rnd.Next(10, 300), y = rnd.Next(10, 300), 70, 40);
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form Form2 = new Form2();
            this.Hide();
            Form2.Show();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            Form3 Form3 = new Form3();
            this.Hide();
            Form3.Show();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            Form4 Form4 = new Form4();
            this.Hide();
            Form4.Show();
        }

    }
}

Форма2:
namespace WindowsFormsApplication1
{
    public partial class Form2 : Form
    {
        Random rnd = new Random();
        public Form2()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form Form1 = new Form1();
            this.Hide();
            Form1.Show();
        }

        private void Form2_Load(object sender, EventArgs e)
        {
            timer1.Start();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            Graphics g=this.CreateGraphics();
            Pen pen=new Pen(Color.FromArgb(rnd.Next(0,256),rnd.Next(0,256),rnd.Next(0,256)),rnd.Next(1,10));
            g.DrawLine(pen, rnd.Next(0, 300), rnd.Next(0, 300), rnd.Next(0, 300), rnd.Next(10, 300));
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            Form Form3 = new Form3();
            this.Hide();
            Form3.Show();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            Form Form4 = new Form4();
            this.Hide();
            Form4.Show();
        }

    }
}

Форма3:
namespace WindowsFormsApplication1
{
    public partial class Form3 : Form
    {
        Random rnd = new Random();
        public Form3()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form Form1 = new Form1();
            this.Hide();
            Form1.Show();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            Form Form2 = new Form2();
            this.Hide();
            Form2.Show();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            Form Form4 = new Form4();
            this.Hide();
            Form4.Show();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void Form3_MouseClick(object sender, MouseEventArgs e)
        {
            int x = e.X, y = e.Y;
            Point[] pn = new Point[10];
            pn[0].X = x; pn[0].Y = y;
            for (int i = 1; i < 10; i++)
            {
                pn[i].X = rnd.Next(0, 300);
                pn[i].Y = rnd.Next(0, 300);
            }
            Graphics g = this.CreateGraphics();
            Pen pen = new Pen(Color.FromArgb(rnd.Next(0, 256), rnd.Next(0, 256), rnd.Next(0, 256)), rnd.Next(1, 10));
            g.DrawCurve(pen, pn);
        }
    }
}

Форма4:
namespace WindowsFormsApplication1
{
    public partial class Form4 : Form
    {
        public int x, y;
        Random rnd = new Random();
        public Form4()
        {
            InitializeComponent();
            g = panel1.CreateGraphics();
        }
        Graphics g;
        private void rect(Graphics g, int x, int y)
        {
            g.FillEllipse(Brushes.SteelBlue, x=rnd.Next(10,300), y=rnd.Next(10,300), 20, 20);
            g.FillRectangle(Brushes.Salmon, x = rnd.Next(10, 300), y = rnd.Next(10, 300), 40, 20);
           
        }

        private void button2_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Form1 Form1 = new Form1();
            this.Hide();
            Form1.Show();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            Form2 Form2 = new Form2();
            this.Hide();
            Form2.Show();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            Form3 Form3 = new Form3();
            this.Hide();
            Form3.Show();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            g.Clear(BackColor);
            this.rect(g,x,y);
           
        }

        private void Form4_Load(object sender, EventArgs e)
        {
            timer1.Start();
           
        }

    }
}