You start with three or four different fabrics. Seam them together. Cut them apart, preferably in an asymmetric fashion (meaning not into nice, neat, matching pieces, but - for example - into one third of one end and two-thirds of the rest).
Seam those together. Easy, peasy machine sewing, straight stitch, in a thread color that will blend into the background. (I used a vanilla white with fabrics of blues and greens and creams and pinks and yellows. Worked fine.) Press open the seams with a hot iron. Cut them apart again. Seam those pieces together. At this point, you should have some fun stuff going on as well as some areas where you wonder how you managed to put that strong floral pattern in so many places that, no matter what, it seems to lay up against another flowered piece in the "partner" piece you are bumping it up against.
Continue until you have the look that you want. If you stop sooner, you'll have nice, long stretches of a pattern with the occasional little block of something else popping up, a quirky surprise. If you continue along for a while - perhaps four sets of sewing and cutting - you'll have a more random look, somewhat crazy quilt and somewhat, dare I say, Gee's Bend-ish. (Ann and Kay, please leave a comment if you read this, pro or con!)
Here's what my patchwork looked like on the wrong side after three go-arounds. And below (I need to write this on my forehead, or at least somewhere on the computer: Blogger loads your photos in the opposite order of whatever literary development you'd planned for the written entry), the fabric after two repeats of cutting and seaming. Still at the rectangular strip, larger block stage of the process.