A fun technique to do on a sunny day. I once did it indoors - years ago - and I still have paintspots on my floor :-(. For this technique you only need fabric, acrylic paints, water and a brush. Fabric was pinned on foam sheets, sprayed with water and diluted acrylic paint was splattered on it. Some more water was added and the foam sheets were put into a vertical position. This way the paint drizzled down and the white fabric got some color as background. After the fabric had dried I again splattered paint on it, but this time I wanted the 'splatters' to remain as they were so I did not spray any water on it and let the fabric dry horizontally.
It looks a bit like the paintings of Jackson Pollock For the moment this fabric will go into my stash. I have no immediate use for it, but one day I will.