A single screw can be used for so much...even for a printed pattern. Pour some fabric paint onto a paper plate or palette pad. Roll a foam rubber roller in paint, covering it well. Roll paint onto the head of the screw (it's best to use a completely flat screw head, not a round one), then make your own impressions on the fabric. Roll on more paint before each print, then it's up to you if you want to design a pattern or just print freely.