Artist mode, toggled by M-x artist-mode, lets you
draw lines, squares, rectangles and poly-lines, ellipses,
and circles with your mouse and/or keyboard. It is extremely
useful when inserting text diagrams or figures in your source
comments.
Beside editing commands, above demonstration uses following Emacs
commands:
C-x b to switch buffers. Originally,
it is bound for `switch-to-buffer'. Instead, binding
`iswitchb-buffer' to C-x b is much easier
to use.
C-x n n to narrow the region,
`narrow-to-region'.
It is very useful to prevent the unwanted change on other portion
of the buffer, and makes the user concentrating on what he or she
want to do. The narrowing is reverted by the command,
C-x n w `widen'.