I used to do this activity with the big girls quite alot when they were younger. I thought L and E might like to try it. The big girls joined in too. To begin draw a picture on a piece of paper with washable markers. Make sure they are washable otherwise the colour will not run. The more colourful the picture the better as there will be more running of colours. Once you've completed your picture, hang it on an easel or since we did ours outside we just clipped it on some branches and spray with the spray bottle. The marker will start to drip and fade a bit giving the picture a soft look. The more you spray the more the colours will continue to run.
paper (fingerpaint paper works great as it can hold alot of water without damaging the paper)