So here is the first result of my intention to actually DO more crafts iso just collecting tons of ideas. (I can see how blogging can be a great way of keeping one to this sort of "commitment").
I saw this idea on Pinterest. Beautifully painted by Geninne http://www.flickr.com/photos/23022617@N00/5079241778/
and tried it on some garden pebbles. Iso paint I used a white "Decorative paint pen" by Rustoleum (from Lifestyle centre's craft section). I repeated all the the lines drawn. Quite happy with the result and the fact that they are weather proof!