This is a good example of line because the lines of paint that bring your eyes down towards the girl holding onto the umbrella. The first thing I see in this picture are the paint drippings and then my eyes go down to the girl with the umbrella.
popping paint filled balloons on a canvas . put paint tape to cover the place to stencil, put paint filled balloons around canvas, pop with darts (slingshots?), let dry, use stencil to add silhouette - love it! Or do the crayon melting thing!