Background with several paths - wpf

Question

Is there a way I can put a background like this in a border:
The problem in there is that both the circle and the square must be a path (in my real problem I actually have 3 paths and they're gradients), and this makes it extremely problematic to resize, align, etc. I saw this solution but I had already tried using a viewbox and it didn't solve my problem.
Is there a way I can combine both the square and the circle into a path and keep the colors, and then set it as a background?
I don't have the real button around here, so I'll post it tomorrow, but it has several gradients to make some glossy effect and some Bezier curves to make the effect more "realistic". In the mean time the effect looks something like this:
Thanks for any help.

Answer 1

Don't quite understand why the ViewBox would not work but alternatively you can use a DrawingBrush, e.g.:
<Border Width="300" Height="300">
<Border.Background>
<DrawingBrush>
<DrawingBrush.Drawing>
<DrawingGroup>
<GeometryDrawing Brush="Blue">
<GeometryDrawing.Geometry>
<RectangleGeometry Rect="0,0,100,100" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
<GeometryDrawing Brush="Red">
<GeometryDrawing.Geometry>
<EllipseGeometry Center="50,50" RadiusX="35" RadiusY="35" />
</GeometryDrawing.Geometry>
</GeometryDrawing>
</DrawingGroup>
</DrawingBrush.Drawing>
</DrawingBrush>
</Border.Background>
</Border>