Another concept that neatly fits is that of need/be necessary to.

go fo komxo.  I need food.
komxo befo go.  Food is necessary to me.

This enables constructions without an object:

komxo befo.   Food is necessary.

And this pair is interesting.

hon sur to stol.  A book is on the table.

to stol besur hon.  The table has a book on top of it.

Interesting that the English construction is so awkward in the second example.

This phenomenon seems to apply to all 'prepositional' forms, and in
doing this, I've noticed that 'prepositional' is somewhat arbitrary, as
in the is in/contains pair.

I have to give credit for this whole notion, which is a simplified
version of the Loglan 'conversion' concept which I suppose JCB
was the first to come up with.  He had conversion particles that
switched the position of subject and object, but he also had other
particles that switched subject with other 'places' equivalent to
indirect objects, etc., which I found unwieldy.  Simplifying it to
a single conversion, I think, makes it highly useful.

One thing I've kept purposefully vague is whether 'be' is a particle
or a prefix.  I really don't know if it makes any difference.  It did
hit me that in the -able construction, 'be' can indirectly also have
the effect of reducing two roots to one.

go kanfey.  I am literate. (I read-can)
to hon bekanfey.  The book is legible. (be-read-can)

go swimfey.  I can swim, am a swimmer, am swim-capable.
to fyume beswimfey.  The river is swimable.