draw a box around the edges:

left side,
right side,
top side,
bottom side,
top left-hand corner,
top right-hand corner,
bottom left-hand corner, and
bottom right-hand corner.

All OK, but this appears
to be an error.

The borders generated are inside borders
(this is also true of curses,
though the fact is not documented).

Note that border and box
may be conditions.

Found poem (erasure) from the Linux Man Pages
Complete text: https://man7.org/linux/man-pages/man3/border.3x.html