This effect was generated in Filter Forge, a Photoshop plugin that allows you to create your own filters.
This is the second of the 'Monster Spawns'. These are spin-offs from my multi-filter, 'The Monster' (which is not released).
These filters are all image filters (using an image component) and a lot of them are noise filters. This one could probably also be classed as a noise fitler.
The original routine from 'the Monster' was modified for this filter. The original was much simpler and I've included it with the filter.
Craig Kraellin Walters monster spawn noise surface refraction curves stairs image