Q:

Get a stacked-element box-shadow effect using only css?

I have a ui element which is supposed to indicate that the represented item will expand into multiple items later in the workflow. My thought is to have it look something like this:

Where the actual image is always different. 
If the element is of this type it gets tagged with a special class expandable-slide This is an alpha version of the application so I don't care to spend very much time putting in new html and widgets, but it is also a Sunday so I'm willing to play around a bit and see if it is possible to get that effect using only css.
It occurs to me that the stacking effect is very similar to a box-shadow, just one that has multiple shadows with slightly different colors and offset by different amounts. I'm not sure that approach will work but that's what I'm currently trying.
Browser requirements are modern chrome/firefox

A:

box-shadow can accept multiple shadow effects to emulate the look you're after.
.expandable-slide {
    margin: 2em 0 0 2em;
    box-shadow: -1em -1em #666,
                -2em -2em #333;
}

Working sample here: http://jsfiddle.net/thefrontender/LwW7g/

