Groups let you wrap a bunch of objects into a new object (a group). To do this, you have to save all the object definitions in a specific file and then open a Group with this file:
metro = Metro()
metro => miin
miin = Group(load:"project/midi_helper.rk" mi/port:0 lua/load:"project/midi_cleanup.lua")
This creates the following setup:

In fact the rubyk planet is the root group. See classes for details.
Funding from the Swiss Federal Office of Culture to write the graphical frontend to rubyk !
General ideas for the design of rubyk.