He likes to start these little toy OS projects. He loses interest and they get abandoned after a little while. He has started (and given up on) several since OpenBeOS (now Haiku) began. Some pieces from previous projects get re-used in each reboot, and there are common themes. Fiorini likes Qt a lot, for example, so that usually features, and he's always interested in new-ish technologies born on Linux, DBus was one example, Wayland is another.
The on-again off-again OS project has been called BeFree, Vision, Mockup, and now apparently Maui. Maybe I missed some names in there.