The BlockSpring library just lets people post their own work onto the BlockSpring home page (www.blockspring.com).
Our library just lets you specify variables in your code that a user should be able to input. Then when you push it to BlockSpring, we generate a forms and other inputs so users can change these variables.
Truth is the BlockSpring library works just as well with non-visualizations. We just figured it was more obvious to have people changing colors in a graph, then adjusting some other input in a js script.
Does that make sense? We're still working on how to phrase this idea :)