How can I get the screen which shows all desktops?

[yinglcs]

How can I get the screen which shows all desktops? I tried 'ctrl-alt-down', but it does not like this:
http://flickr.com/photos/46509322@N00/578163490/
* how to config it to have reflection?
* how to config it to show just 4 desktops? for me it wraps around forever.

Thank you.

[crdlb]

That is the expo plugin. When it's enabled, it can be triggered by putting the mouse in the top left corner or with <super>e. It will have the reflective effect by default. Also it's possible to add reflection to the ctrl+alt+down (unfold cube) effect by turning on cube reflection.