Definitely horizontal. I have a basic algorithm for garbage collection though: When there is no more room for new stuff to be laid out (i.e., it would introdu

Definitely horizontal. I have a basic algorithm for garbage collection though: When there is no more room for new stuff to be laid out (i.e., it would introduce structural unsoundness into the heaving mass that covers my desk), I sift through and make two piles: things I recognise, and things I don't. The "things I don't recognise" are usually papers I printed and have never read (having long since abandoned whatever the project is that I printed it for), brochures and leaflets I'm handed as I walk across campus (which I deposit on my desk as soon as I reach my office), and things which are so out of date as to be irrelevant (e.g. a library notice for a book I returned months ago). All of this stuff goes into the recycling bin. The stuff I might considering looking at again forms a pile and gets pushed to one of the back corners of the desk. Naturally, I dismantle the "keep" pile occasionally while looking for something, which redistributes things onto the desk so that they get re-considered during the next garbage collection run, so I find the pile is usually remains reasonably "fresh". Stating it this way makes it sound like I've put a lot of thought into this, but I really haven't. It's just a natural way of working for me. My desk looks messy and disorganised, but I rarely have trouble finding things - it's either spread out on my desk, in the pile, or gone forever.