public Form1()
        {
            InitializeComponent();
            Width = 500;
            Height = 400;
            AutoSizeMode = AutoSizeMode.GrowAndShrink;
        }

        static Random rnd = new Random();
        Point p = new Point();

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

        void SetPoint()
        {
            p.X = rnd.Next(20, 400);
            p.Y = rnd.Next(20, 350);
            BackColor = Color.White;
            Text = "Лаб.Раб. №1_3. Хохлов Даниил";
        }
        private void Form1_MouseClick(object sender, MouseEventArgs e)
        {
            double pos = Math.Sqrt((p.X - e.X) * (p.X - e.X) + (p.Y - e.Y) * (p.Y - e.Y));
            int digit = 0;
            if (pos <= 20)
            {
                BackColor = Color.Black;
                digit = 10;
                Text = "Лаб.Раб. №1_3. Хохлов Даниил " + digit + "!";
                MessageBox.Show("Поздравление!");
                digit = 0;
                SetPoint();
            }
            if (pos <= 30 && pos > 20)
                digit = 9;
            if (pos <= 40 && pos > 30)
                digit = 8;
            if (pos <= 50 && pos > 40)
                digit = 7;
            if (pos <= 60 && pos > 50)
                digit = 6;
            if (pos <= 70 && pos > 60)
                digit = 5;
            if (pos <= 80 && pos > 70)
                digit = 4;
            if (pos <= 90 && pos > 80)
                digit = 3;
            if (pos <= 100 && pos > 90)
                digit = 2;
            if (pos <= 110 && pos > 100)
                digit = 1;
            if (pos > 110)
                digit = 0;
            switch (digit)
            {
                case 0: BackColor = Color.White; break;
                case 1: BackColor = Color.FromArgb(220, 220, 220); break;
                case 2: BackColor = Color.FromArgb(215, 215, 215); break;
                case 3: BackColor = Color.FromArgb(211, 211, 211); break;
                case 4: BackColor = Color.FromArgb(207, 207, 207); break;
                case 5: BackColor = Color.FromArgb(200, 200, 200); break;
                case 6: BackColor = Color.FromArgb(192, 192, 192); break;
                case 7: BackColor = Color.FromArgb(185, 185, 185); break;
                case 8: BackColor = Color.FromArgb(169, 169, 169); break;
                case 9: BackColor = Color.Gray; break;
            }
            Text = "Лаб.Раб. №1_3. Хохлов Даниил " + digit + "!";
        }