<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="SolidColorBrush Animation Example" Background="White"> <StackPanel> <Rectangle RadiusX ="15" RadiusY ="15" Height ="40" Width ="100"> <Rectangle.Fill> <LinearGradientBrush StartPoint="0,0.5" EndPoint="1,0.5"> <GradientStop Color="LimeGreen" Offset="0.0" /> <GradientStop Color="Orange" Offset="0.25" /> <GradientStop Color="Yellow" Offset="0.75" /> <GradientStop Color="Blue" Offset="1.0" /> </LinearGradientBrush> </Rectangle.Fill> </Rectangle> </StackPanel> </Window>