Designing fabric without a computer

So I have to admit here that I'm not the most tech savvy girl around.  As a sewist--not to be confused with a sewer, right?--I love the idea of designing my own fabric but am intimidated by the prospect of learning my way around Photoshop and Illustrator software.  This is why I was intrigued when Marcy at Oonaballoona sent me a photo and told me about her method of creating the fabric she wanted.    Here is her canvas, along with an explanation of her process:

The canvas (which is huge... 5 by 5 feet) had been painted over many, many times in a vain attempt to come up with something I liked.  My husband liked the 10th attempt so much he wouldn't let me paint over it, but as I couldn't stand to look at it, I decided covering it in fabric would keep us both happy.  I actually wanted a specific piece of Ikea fabric with a sort of organic cityscape on it, but when I got there I found it had been discontinued.  I couldn't find another ready made scene that I liked, so I decided to create my own. I picked a few patterns I liked (one form Ikea, one from Urban Outfitters) dug through the scrap bin and came up with my treehouse scene.  I started by putting the background together, then did a freehand of the birds & branches on velvet & leather.  I quilted the freehand shapes onto the background with my trusty featherweight 221 (handled the entire job with just a regular foot, LOVE that machine), and with my heavy duty staple gun secured it to the canvas.

Marcy says she'd like to do more of these and condense them down into a smaller repeating pattern--with copyright-free background fabrics, of course!