Одинаковая скорость при выполнении анимации

[Slant-shadow]

Всем привет.
Можете подсказать, как сделать чтобы скорость объектов при выполнении анимации была одинаковой?

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.Animation;using System.Windows.Media.Imaging;using System.Windows.Navigation;using System.Windows.Shapes; namespace WpfApplication2{    /// <summary>    /// Interaction logic for MainWindow.xaml    /// </summary>    public partial class MainWindow : Window    {        public MainWindow()        {            InitializeComponent();            ta.Completed += ComplitedAnimation;             ta.FillBehavior = FillBehavior.Stop;            ta.Duration = TimeSpan.FromSeconds(0.5);            ta.Duration = new Duration(new TimeSpan(0, 0, 5));        }         ThicknessAnimation ta = new ThicknessAnimation();         public double main_window_width { get { return main_window_grid.ActualWidth; } }        public bool fl1;        public bool fl2;        private Thickness marginBackup;         private void ComplitedAnimation(object sender, EventArgs e)        {                       if (fl1 == true)            {                fl1 = false;                grid_blue.Visibility = Visibility.Visible;                grid_red.Margin = marginBackup;            }             if (fl2 == true)            {                fl2 = false;                grid_red.Visibility = Visibility.Collapsed;                grid_blue.Margin = marginBackup;            }         }         private void Move_Animation(object sender, RoutedEventArgs e)        {            fl1 = true;            ta.From = new Thickness(main_window_width, 0, 0, 0);            ta.To =  grid_red.Margin;            marginBackup =  grid_red.Margin;                      grid_red.BeginAnimation(MarginProperty, ta);            grid_red.Visibility = Visibility.Visible;             ta.From = grid_blue.Margin;            ta.To = new Thickness(0, 0, main_window_width, 0);            grid_blue.BeginAnimation(MarginProperty, ta);        }    }}

<Window x:Class="WpfApplication2.MainWindow"        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"        Title="MainWindow" Height="350" Width="525">    <Grid x:Name="main_window_grid">        <Grid>            <Grid x:Name="grid_blue"  Height="200" Width="350" Background="Blue" Margin="0,0,0,0">            <Button Name="bt_blue" Width="50" Height="50" Margin="200,100,0,0" Content="button" Click="Move_Animation"></Button>        </Grid>        <Grid x:Name="grid_red"  Height="200" Width="350" Background="red" Margin="0,0,0,0" Visibility="Collapsed">                <Button Name="bt_red" Width="50" Height="50" Margin="200,100,0,0" Content="button"></Button>        </Grid>        </Grid>    </Grid></Window>