Circle

 1 using System;
 2 using System.Collections.Generic;
 3 using System.ComponentModel;
 4 using System.Data;
 5 using System.Drawing;
 6 using System.Linq;
 7 using System.Text;
 8 using System.Threading.Tasks;
 9 using System.Windows.Forms;
10 
11 namespace Circle
12 {
13     public partial class Form1 : Form
14     {
15         public Form1()
16         {
17             InitializeComponent();
18         }
19 
20         Random random = new Random();
21 
22         Color getRandomColor()
23         {
24             return Color.FromArgb(
25                  random.Next(256),
26                  random.Next(256),
27                  random.Next(256));
28         }
29 
30         protected override void OnPaint(PaintEventArgs e)
31         {
32             Graphics g = this.CreateGraphics();
33             int x0 = this.Width / 2;
34             int y0 = this.Height / 2;
35 
36             for (int r = 0; r < this.Height / 2; r++)
37             {
38                 g.DrawEllipse(
39                     new Pen(getRandomColor(), 1),
40                     x0 - r,
41                     y0 - r/2,
42                     r * 2,
43                     r * 2
44                 );
45             }
46             g.Dispose();
47         }
48     }
49 }