C# Logical Schema

[shadow2002]

Please help, I need a Logical schema after the code below
A number is initialized to 0 and displayed.
When a button is pressed, the existing number is incremented by 10 and displayed.
If the number reaches 100, it is decremented by 10 until it reaches 0.
If the number reaches 0, it is incremented by 10 until it reaches 100.
The program continues this way until it is exited.

using System;
using System.Drawing;
using System.Windows.Forms;

namespace l2
{
public partial class Form1 : Form
{
int count = 0, sp = 5, x0 = 25, y0 = 300, y1 = 301;
bool sem = true;

public Form1()
{
InitializeComponent();
}

private void label1_Click(object sender, EventArgs e)
{
}

private void button1_Click(object sender, EventArgs e)
{
using (Graphics desen = this.CreateGraphics())
{
using (SolidBrush pensula_albastra = new SolidBrush(Color.Blue))
using (SolidBrush radiera = new SolidBrush(this.BackColor))
{
desen.FillRectangle(radiera, x0, y0, sp, y1 - y0);

if (sem)
{
if (count < 100)
{
count += 10;
label1.Text = count.ToString();
y0 -= 10;
}
else
{
sem = false;
count -= 10;
label1.Text = count.ToString();
y0 += 10;
}
}
else
{
if (count > 0)
{
count -= 10;
label1.Text = count.ToString();
y0 += 10;
}
else
{
sem = true;
count += 10;
label1.Text = count.ToString();
y0 -= 10;
}
}

desen.FillRectangle(pensula_albastra, x0, y0, sp, y1 - y0);
}
}

x0 += 9;
}
}
}