form1

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication11
{
    public partial class Form1 : Form
    {
        Bitmap b;
        Graphics g;
        Pen p;
        Line line1, line2;
        //Rectangle rec;


        public Form1()
        {
            InitializeComponent();
            Init();
            Draw();

        }

        private void Init()
        {
            line1 = new Line(100, 100, 250, 10);
            line2 = new Line(250, 10, 400, 100);
            //rec = new rectangle(100, 100, 400, 300);
            p = new Pen(Color.Chocolate, 2);
            b = new Bitmap(pictureBox1.Width, pictureBox1.Height);
            g = Graphics.FromImage(b);
            pictureBox1.Image = b;

        }



        private void pictureBox1_Click(object sender, EventArgs e)
        {

        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Draw();
        }

        public void Draw()
        {
            Pen p = new Pen(Color.Chocolate, 20);
            Bitmap b = new Bitmap(pictureBox1.Width, pictureBox1.Height);
            Graphics g = Graphics.FromImage(b);
            Point p1 = new Point(100, 100);
            Size s = new Size(300, 200);
            Rectangle r = new Rectangle(100, 100, 300, 200);

            g.DrawLine(p, 100, 100, 250, 10);
            g.DrawLine(p, 250, 10, 400, 100);

            g.DrawLine(p,450,30,600, 300);
            g.DrawLine(p,300,300, 450,30);


            g.DrawRectangle(p, r.x1, r.x2, r.y1, r.y2);

            pictureBox1.Image = b;
          }

        private void Draw(Line line)
        {
        g.DrawLine(p, line.x1, line.y1, line.x2, line.y2);

        }

        private void Draw(Rectangle r)
        {
            g.DrawRectangle(p, r.x1, r.x2, r.y1, r.y2);
        }
}
}