gistfile1.txt

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;

namespace DemoMovingObject
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private DispatcherTimer timer = new DispatcherTimer();
        private Rectangle fallingSquare;
        private int startTop = 80;
        private int currentTop;
        private int bottom = 330;

        public MainWindow()
        {
            InitializeComponent();
            InitializeCanvas();
            InitTimer();
        }

        private void InitTimer()
        {
            timer.Interval = new TimeSpan(0,0,0,0,25);
            timer.Tick += DropMotion;
        }

        private void DropMotion(object sender, EventArgs e)
        {
            const int updateDistance = 10;
            if (currentTop + updateDistance <= bottom)
            {
                currentTop += updateDistance;
                Canvas.SetTop(fallingSquare, currentTop);
            }
            else
            {
                timer.Stop();
            }
        }

        private void DrawLine(int x1, int y1, int x2, int y2)
        {
            Line line = new Line();
            line.Stroke = Brushes.LightGray;
            line.StrokeThickness = 2;
            line.X1 = x1;
            line.X2 = x2;
            line.Y1 = y1;
            line.Y2 = y2;
            Canvas1.Children.Add(line);
        }

        private void InitializeCanvas() 
        {
            DrawLine(5, 20, 5, 380);
            DrawLine(75, 20, 75, 380);
            DrawLine(155, 20, 155, 380);
            DrawLine(230, 20, 230, 380);
            DrawLine(5, 380, 230, 380);
        }

        private void Button1_Click(object sender, RoutedEventArgs e)
        {
            DropSquare(15, 330);
        }

        private void DropSquare(int slot, int stopTop)
        {
            fallingSquare = newSquare(slot);
            currentTop = startTop;
            bottom = stopTop;
            timer.Start();
        }

        private Rectangle newSquare(int slot)
        {
            const int size = 50;
            Rectangle square = new Rectangle();
            square.Fill = Brushes.Gold;
            square.Width = square.Height = size;

            Canvas1.Children.Add(square);
            Canvas.SetTop(square, startTop);
            Canvas.SetLeft(square, slot);
            
            return square;
        }
    }
}

xaml

<Window x:Class="DemoMovingObject.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="450" Width="650">
    
    <Window.Resources>
        <Style TargetType="Canvas">
            <Setter Property="Background" Value="Navy" />
            <Setter Property="Height" Value="400" />
            <Setter Property="Width" Value="600" />
        </Style>
        <Style TargetType="Button">
            <Setter Property="Background" Value="Lime" />
            <Setter Property="Foreground" Value="White" />
            <Setter Property="Margin" Value="10,20,10,5" />
            <Setter Property="Padding" Value="20,5,20,5" />
            <Setter Property="FontSize" Value="25" />
        </Style>
    </Window.Resources>
    <Grid>
        <Canvas Name="Canvas1" Height="400" Width="600" Background="Navy">
            <StackPanel Orientation="Horizontal">
                <Button Name="Button1" Content="1" Click="Button1_Click" />
                <Button Name="Button2" Content="2" />
                <Button Name="Button3" Content="3" />
            </StackPanel>
        </Canvas>
    </Grid>
</Window>