[texhax] plain TeX: `No room for a new \fam'

[Karl Berry]

Hi Rodolfo,

    I'm a plain TeX user, and have already loaded 16 \newfamS.  Is there
    any way to get round TeX's complain?  To, say, create room for
    another 16 families?

1) Use luatex or xetex.
2) Deallocate/allocate families in between formulas as needed.

If you search for something like 
  more than 16 math families tex
you'll get a bunch more q&a's on this topic.

Hope this helps,
k