<Window x:Class="Workspace.DockExample"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Workspace" Width="640" Height="480">
<Ellipse Margin="15,0,0,0" Width="200" Height="200" Stroke="Red" StrokeThickness="1">
<Ellipse.Fill>
<DrawingBrush Viewport="0,0,150,50" ViewportUnits="Absolute" TileMode="Tile">
<DrawingBrush.Drawing>
<DrawingGroup>
<DrawingGroup.Children>
<ImageDrawing ImageSource="c:\image.JPG" Rect="0,0,100,50" />
<ImageDrawing ImageSource="c:\image.JPG" Rect="100,0,50,50" />
</DrawingGroup.Children>
</DrawingGroup>
</DrawingBrush.Drawing>
</DrawingBrush>
</Ellipse.Fill>
</Ellipse>
</Window>