Uno Test App used in Twitter video

MainPage.xaml

<Page x:Class="UnoApp8.MainPage"
      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
      xmlns:local="using:UnoApp8"
      xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
      Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
      mc:Ignorable="d">

    <Grid>
        <Border Width="300"
                Height="200"
                Background="Red"
                CornerRadius="8"
                PointerExited="Rectangle_PointerReleased"
                PointerMoved="Rectangle_PointerMoved"
                PointerPressed="Rectangle_PointerPressed"
                PointerReleased="Rectangle_PointerReleased"
                RenderTransformOrigin="0.5,0.5">
            <Border.RenderTransform>
                <CompositeTransform x:Name="rectTransform" />
            </Border.RenderTransform>
            <TextBlock HorizontalAlignment="Center"
                       VerticalAlignment="Center"
                       FontSize="44"
                       Foreground="White"
                       Text="Uno Platform" />
        </Border>
    </Grid>
</Page>

MainPage.xaml.cs

using Microsoft.UI;
using Microsoft.UI.Xaml.Input;
using Microsoft.UI.Xaml.Shapes;
using Windows.Foundation;

namespace UnoApp8 {
    public sealed partial class MainPage : Page {

        private bool _isDown;
        private Point _orgPoint;

        public MainPage() {
            this.InitializeComponent();
        }

        private void Rectangle_PointerMoved(object sender, PointerRoutedEventArgs e) {
            if (_isDown && sender is Border border) {
                border.Background = new SolidColorBrush(Colors.Orange);
                var p = e.GetCurrentPoint(null).Position;
                rectTransform.TranslateX = -(_orgPoint.X - p.X);
                rectTransform.TranslateY = -(_orgPoint.Y - p.Y);
            }
        }

        private void Rectangle_PointerReleased(object sender, PointerRoutedEventArgs e) {
            if (_isDown && sender is Border border) {
                border.Background = new SolidColorBrush(Colors.Red);
                _isDown = false;
            }
        }

        private void Rectangle_PointerPressed(object sender, PointerRoutedEventArgs e) {
            if (sender is Border border) {
                border.Background = new SolidColorBrush(Colors.Blue);
                _isDown = true;
                _orgPoint = e.GetCurrentPoint(null).Position;
                _orgPoint.X -= rectTransform.TranslateX;
                _orgPoint.Y -= rectTransform.TranslateY;
            }
        }
    }
}