Using Storyboard.TargetProperty, the properties of an object can be assigned with values. The objects are referred by Storyboard.TargetName attribute. The following snippet illustrates the change of width and color of a rectangle object.
<Storyboard>
<DoubleAnimation Storyboard.TargetName="MyRectangle" Storyboard.TargetProperty="Width" From="150" To="275" Duration="0:0:2" />
<ColorAnimation Storyboard.TargetName="MySolidColorBrush" Storyboard.TargetProperty="Color" From="Green" To="Red" Duration="0:0:2" />
</Storyboard>