The first, SPLIT, should work on any II.  RUN SPLIT.MAIN
It splits the screen, with text on top and lo-res graphics on the bottom, by
reading the floating bus.  It's from an article in Softtalk.

The second, MERGE, displays text and graphics simultaneously.  It uses the
vertical blanking interrupt, so it's transparent to foreground programs, but
only works on earlier IIc's.  I wrote it and it's free, of course.
EXEC MERGE for a demo.