I've been working on a good methodology for producing stairs that look like stairs, and I'm not quite there yet. Here's an example, showing a straight staircase descending north to south (100dpi 5' per inch scale). It's not terrible, it's not even bad, but I think there's room for improvement, especially at the bottom, where the descent shadow mixes with the final step shadow on the floor, producing a missing step. My basic process (Gimp):

Lay out steps using standard fill techniques.
Build a series of step shadows using Gaussian Blur in a Soft Light layer.
Build a single gradient descent shadow covering the steps in a second Soft Light layer.

The walls are just black placeholders, and they have a light shadow applied.

Click image for larger version. 

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Any thoughts on how to improve this?