2. After the pencil shapes are drawn, they are colored in with a NON-permanent, waterbase marker. This is the time to use those cheap store markers as you actually will be wanting the colors to bleed.
3. Use a small cup of water to drop several puddles on their artwork with a brush or dropper. If you pick up the paper and roll the water around a bit, it should start to make lots of colored streaks and blobs. Repeat this until almost all of the artwork is filled with wiggly colored lines. Let dry overnight.
4. Now comes the fun part. Take a thin black Sharpie and tracing all the organic shapes that were made from the running water. Work slowly to trace all the wonderful edges, both inside and outside the colored shapes. The more time you put into the tracing, the better the artwork will look.