The above pattern came about through the use of tissue paper to print on. Because that part of the screen got a lot of ink pushed through, the tissue paper buckled when printed on, creating this rather appealing pattern.
The above marks were made by spraying water onto the ink on the screen before printing. Spraying the screen helps keep the ink to the consistency for printing, as opposed to drying on the screen.
The image above is formed from a number of prints of the same design, but each time I printed, I turned the paper around to help reduce the predictability of the pattern.