Have a look at the picture below:

![skyscrapers](https://i.stack.imgur.com/8IcjS.png)

The blue boxes are divs. Now what I am trying to do is to implement a sort of 2.5D functionality:

I would like the grey shadows to be somewhat 3D-ish. At first I was thinking to assign to the box-shadow value the "Y" axis like this:

```
"box-shadow: -5px -5px 10px" + value.tallness +  "#888"

```

but the result is the above image.

Any idea on how to make the shadow on one side only, like there was a light source from somewhere?

EXTRA - what about a *moving* "light source"?