Tried defining an initial scene for the game.

Discovered the prewritten code to manage objects and keep track of what's in what is not really usable.
A container has to have the type 'Container' but also needs to have its own more specific type, such as Chair, Room, Suitcase.
It's not clear to me that there's really a hierarchy of types.  I'll have to let each thing be part of several types.  I suppose these might be like the Coppo-Desani intersection types.  Tomorrow I'll experiment and find out what works.
I guess it's entirely possible that the old code I intended to use will be almost entirely replaced before the week is over.

(added later) Hmmm.  I seem to remember that my old data structures had provision for one kind being a subkind of another.  It probably won't work because I never tested it.  But an explicit type-check certainly doesn't know about any of this stuff.