attention k3n:
I've held my hinged mirror and a white piece of paper (to make a triangle) up to the computer screen to see if a certain fabric would work for a OBW. If you can only buy fabric online, this might work for you too. Of course you need to get the fabric swatch enlarged as much as possible before you try this. Also when ordering, if you can mention you need 6 repeats or 8 or whatever you want. Some places will give you exactly what you need instead of half yard or more amounts.