This is what clients have asked for more than any other 2D texture. It's a simple network built in TOPs. The main difference in this network (you'll notice it has a lot of elements I use often) is that the Slope strength value in the feedback loop has a negative value. It causes these open line shapes created by the noise/edge combination to collapse into smaller closed shapes (kind of like squirmy little pills).
Files available for Vibe Tier and up!