Question: I've been trying to get my head around XAML and it's namespaces and I just cannot seem to get the logics of things. For example, I'm trying to animate a gridrow's GridLength property following a tutorial. I can get the sample code to run just fine. But trying to actually port the features into my own code seems to be impossible. I always run into odd errors which doesn't occur in the source code. Animating the GridLength property isn't possible, so I need to create a new .vb file containing the code making it possible. 

But trying to actually reach what's in there I can't get to work.

In my Window.xaml file I have this at the top:

```
xmlns:gridanim="clr-namespace:HDI_WPF_GridAnimation_vb"

```

Which targets a GridLengthAnimation.vb file. In that file you have this:

```
Imports System.Windows.Media.Animation
Imports System.Windows

Public Class GridLengthAnimation
    Inherits AnimationTimeline

```

Back in the Window.xaml, getting contact with "GridLengthAnimation" is impossible:

```
<gridanim:GridLengthAnimation></gridanim:GridLengthAnimation>

```

I get an error message saying:

```
The name "GridLengthAnimation" does not exist in the namespace "clr-namespace:HDI_WPF_GridAnimation_vb".

```

What is causing the issue?

Answer: 
Patterns for object creation include `Builder`, `Factory`, and `Prototype`. Wikipedia has a [fairly detailed list](http://en.wikipedia.org/wiki/Design_pattern_%28computer_science%29#Classification_and_list).
There are two or three patterns for object creation. The most common is the factory, which seems applicable in this hierarchy. I don't quite recall the other ones (nor how many there are), but I think another one is called prototype.

If you care about such things, get the book on design patterns.