Maybe this tutorial can help you.
It is about System.Drawing.Graphics,
GDI+ Tutorial for Beginners[
^]
You can start with
using System.Drawing;
using System.Windows.Forms;
namespace WindowsFormsApp3
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Paint(object sender, PaintEventArgs e)
{
var myColor = ColorTranslator.FromHtml("#0C59A6");
e.Graphics.FillRectangle(new SolidBrush(myColor), 0, 0, 100, 100);
e.Graphics.FillRectangle(new SolidBrush(myColor), 150, 0, 100, 100);
e.Graphics.FillRectangle(new SolidBrush(myColor), 0, 150, 100, 100);
e.Graphics.FillRectangle(new SolidBrush(myColor), 150, 150, 100, 100);
}
}
}
This will draw the top left rectangles of the greek flag.
The missing parts is your homework.