The Flow plugin provides side-by-side metric visualization on SVG diagrams. You provide the SVG diagram along with configuration on how you want the diagram to behave. The panel then combines these with your time-series data to bring your diagram to life.
Follow the plugin Getting Started guide to understand the target audience, feature set and how to use.
Go to the Grafana Getting Started guide to get going with downloading a fork and setting up your test environment. Once up you'll find dashboards available (sourced from the provisioning directory) that act as demonstrators for the functionality.