How flowG fits the openIE ecosystem

Five public projects share a common substrate:

                       lux-lang   jmax    joule-lang
                            \     |     /
                             \    |    /
                              ▼   ▼   ▼
                             flow-g  ←  ← ← jouledb (metered persistence)
                                ▲
                                │
                          substrate-energy
                              (joules)

[Detailed design discussion in v0.2.0 docs.]