BrownianBotsWithTimerEvent

using System;
using System.Collections.Generic;
using System.Timers;
class Program
{
    static List<Bot> bots = new List<Bot>();
    static void Main()
    {
        Console.CursorVisible = false;

        Bot bot1 = new Bot(10, 20, ConsoleColor.Yellow);
        bot1.Moved += HandleBotMoved;
        bots.Add(bot1);

        Bot bot2 = new Bot(20, 10, ConsoleColor.Red);
        bot2.Moved += HandleBotMoved;
        bots.Add(bot2);

        bot1.Start();
        bot2.Start();

        Console.ReadLine();

        foreach (var bot in bots) bot.Stop();
    }
    static void HandleBotMoved(Bot bot)
    {
        Console.ForegroundColor = bot.color;
        Console.SetCursorPosition(bot.x_prev, bot.y_prev);
        Console.Write(' ');

        Console.SetCursorPosition(bot.x, bot.y);
        Console.Write('*');
    }
}
class Bot
{
    public int x_prev = 0;
    public int y_prev = 0;
    public int x = 0;
    public int y = 0;
    public ConsoleColor color = ConsoleColor.White;
    Timer timer;
    public event Action<Bot> Moved;
    static Random random = new Random();
    static object syncObj = new object { };
    public Bot(int x, int y, ConsoleColor color)
    {
        this.x = x;
        this.y = y;
        this.color = color;
        timer = new Timer(100);
        timer.Elapsed += OnTimerEvent;
    }
    ~Bot()
    {
        timer.Dispose();
    }
    public void Start()
    {
        timer.AutoReset = true;
        timer.Enabled = true;
        timer.Start();
    }
    public void Pause()
    {
        timer.Enabled = false;
    }
    public void Stop()
    {
        timer.Stop();
    }
    void OnTimerEvent(Object source, ElapsedEventArgs e)
    {
        lock (syncObj)
        {
            x_prev = x;
            y_prev = y;
            x += random.Next(-1, +2);
            if (x < 0) x += 1; if (x > 20) x -= 1;
            y += random.Next(-1, +2);
            if (y < 0) y += 1; if (y > 20) y -= 1;
            Moved?.Invoke(this);
        }
    }
}