inds of Lego sets you can build some kinds of things ... with others
    you build other kinds of things.  Are we looking at the same thing?

well, say we fix on a particular set !A! of alphabet blocks.
we want there to be this biggest possible, freely-generated
formal language X = !A!* that can be built from our building
blocks, and with lego blocks i would have to worry about all
of the extra built-in constraints from the get-go.

any old formal language L on this alphabet is L c X = !A!*.

now, there are