WPF Animations - where to place them

In previous blogs , I talked about the classes in animation and what the different types are; not to mention how great WPF is that doing animations is so easy

Now, where do you place animations in xaml?

Firstly, they have to be defined within a storyboard.
A storyboard (I’ve always felt a slightly odd name for the class) can contain a number of animations, and it is the storyboard that controls the playing of the animations.

Here is n animation within a storyboard that makes the textbox widen when you put the mouse over the textbox: