Coding in non-editable code

Weird programming language idea.  So in one of my favorite video games, Riven (the sequel to Myst)  there's this thing where people write books that describe places and then they can literally visit those places.  An oddity of this is that they are basically writing code, but since they are literally writing symbols on paper with ink symbols cannot be literally erased.

It is mentioned in the lore somewhere that there's at least a symbol you can add to the end that can cancel out stuff before it but anyway.

The idea then is this:
A language designed to be written once, in ink, where anything you write can no longer be directly erased.  All edits to your code, if you didn't write it correctly in the beginning, must thus simply be added on to the string of symbols already there.

As a bonus!  This could maybe work in the direction of a spoken programming language, since what you say in real life to another person cannot be unsaid.