So I folded under pressure (from myself mainly) and bought a Gelli plate. What fun!! - although anyone who's got one will know that anyway. I've been playing this afternoon with no plan in mind at all. Just me and my stencils and acrylic paints.
Here's a selection of some of the samples:
Love the detail on the one below. I've got a bit of a thing for blood cells and histopathology slides so these two samples are right up my street.
... and if you don't like the result you can just keep on layering and adding different colours and stencil patterns or using anything that you can make a pattern with - eg a comb, bottle tops, bubble wrap, the plastic wrapping from your satsumas - you get the idea...
I had to try fabric too..
... it seems to work just as well (more cellular patterns).
If you haven't got one and like experimenting and getting messy, I can highly recommend a Gelli plate to keep you amused. :)