We've been learning about art lately, and have been noticing that art comes in all sorts of shapes and sizes... and this project demonstrates that idea fantastically!
Use any color of heavy paper. (You could even use a piece of drawn-on scratch paper if you like!) Alternately, you could use permanent markers instead of watercolor paints.
My children smeared glue stick all over the page to adhere the string. You could just as easily put a bit of school glue in a small pot and add water, then brush the glue on with a paintbrush.
When the string was arranged 'just so', gluing down some stray ends and loops as necessary, the children added more glue...
...then we pressed foil all over the grooves of the string. Very carefully and firmly, Maddie and Trev pressed and creased their creations... they wanted lots of detail!
When the sections were filled in just as the children liked --"This is such a neat project!" -- we left the paintings alone so that the water could evaporate.