picture-self-insert
picture-self-insert is an interactive compiled Lisp function in `picture.el
'.
(picture-self-insert ARG)
Insert this character in place of character previously at the cursor.
The cursor then moves in the direction you previously specified
with the commands `picture-movement-right', `picture-movement-up', etc.
Use "M-x command-apropos picture-movement" to see those commands.