Hi, klaws. Welcome! Glad you're going to play with us.
You can send whatever you'd like in fabric. Just keep in mind that it is stripes, so patterns would be limited for it. You specify what you want (or don't want) for background and accompanying colors. The only thing you can't specify is a specific fabric or what pattern we decide to make for you. We all try to stick to your requests as closely as we can. So far it seems to work very well.