In the book "Experiments with Matlab" of Cleve Moler (free ebook)
with source code
is an experiment mandelbrot.m.
When you run it, you should get a graphical menu.
It worked fine in R2017a, but now in R2019b there seem to be checks that are more strict:
Error:File: mandelbrot.m Line: 54 Column: 14
Identifier 'depth' is not a function or a shared variable. To share 'depth' with nested function,
initialize it in the current scope. For more information, see Sharing Variables Between Parent and Nested Functions.
I have no clue where and what to change.
Do you know / have experience in what changed recently in matlab R2019b?