Как обратиться к треугольнику через radioButton и заставить его мигать?

        TriangleDraw triangleDraw1;
        Random rnd = new Random();
        private void Form1_Load(object sender, EventArgs e) {
            triangleDraw1 = new TriangleDraw(this);
            triangleDraw1.Left = 100;
            triangleDraw1.Top = 100;
        }
 
        private void timer1_Tick(object sender, EventArgs e) {
            if (triangleDraw1 == null) return;
            triangleDraw1.Fill = new SolidBrush(Color.FromArgb(rnd.Next(0, 255), rnd.Next(0, 255), rnd.Next(0, 255)));
        }

using System;
using System.Drawing;
using System.Windows.Forms;
 
public class TriangleDraw : IDisposable {
 
    private Control _Parent = null;
    public Control Parent { get => _Parent; }
    private Size _Size = new Size(100, 100);
    public Size Size {
        get => _Size;
        set {
            _Size = value;
            _Parent?.Refresh();
        }
    }
 
    private Point _Location = new Point();
    public Point Location {
        get => _Location;
        set {
            _Location = value;
            _Parent?.Refresh();
        }
    }
    private Brush _Fill = Brushes.Black;
    public Brush Fill {
        get => _Fill;
        set {
            _Fill = value;
            _Parent?.Refresh();
        }
    }
    public TriangleDraw(Control control) {
        _Parent = control;
        _Parent.Paint += OnPaint;
    }
    private void OnPaint(object sender, PaintEventArgs e) {
        if (_Parent == null) return;
        e.Graphics.FillPolygon(Fill, new PointF[] {
            new PointF(Location.X, Location.Y + Size.Height),
            new PointF(Location.X + (Size.Width / 2), Location.Y),
            new PointF(Location.X + Size.Width, Location.Y + Size.Height)
        });
    }
    public void Dispose() {
        if (_Parent != null) {
            _Parent.Paint -= OnPaint;
            _Parent.Refresh();
            _Parent = null;
        }
    }
 
    public int Left {
        get => Location.X;
        set => Location = new Point(value, Location.Y);
    }
 
    public int Top {
        get => Location.Y;
        set => Location = new Point(Location.X, value);
    }
 
    public int Width {
        get => Size.Width;
        set => Size = new Size(value, Size.Height);
    }
 
    public int Height {
        get => Size.Height;
        set => Size = new Size(Size.Width, value);
    }
}

 private void Form1_Paint(object sender, PaintEventArgs e)
        {
 
            using
                (Graphics g = e.Graphics)
            {
                using (Pen pen = new Pen(Color.Black))
                {
                    g.DrawLine(pen, 200, 200, 300, 300);
                    g.DrawLine(pen, 100, 300, 300, 300);
                    g.DrawLine(pen, 100, 300, 200, 200);