@Christian Wolinski You can give a name to that "unnamed module" if you want:

main:= ():
main:-`+`(1, 1.1);

Try uploading the worksheet with the "Insert contents" button instead of the "Insert link" button. In my experience, this always inserts the link even if it fails to insert the contents.

@Christian Wolinski Sorry, I misread your Question. I read "undo" as "do".

Have you read the help page ?overload and not understood it? Or were you not aware of the help page?

I wrote:

• It's asking min for the position in the list of the minimal entry rather than the entry itself.

And the reason that I did that is that the Question asks not for the minimal value of F but rather for the value of z that produces the minimal value of F.

@nmacsai If you simply omit the background option from the plot command, does that do what you want?

@Ronan The index is an option to min or max and isn't connected to solve. It's asking min for the position in the list of the minimal entry rather than the entry itself.

@Christian Wolinski minimize in Maple 2022.1 doesn't complete (in reasonable time) for me either. 

What could you possibly see from a contour plot of only 21 function values of which 19 are identically 0?

@south The assignment of initial conditions should be a single assignment for multiple initial conditions:

ics:= y(0)=1, D(y)(0)=0;

Doing as you did, the second assignment erases the first.

This is obviously a Question, not a Post. It was a Question when I first saw it. I don't know why someone converted it to a Post.

@smithss This new problem is so much larger than the first that it's utterly inconceivable that it could be solved by Kitonum's method even on the largest and fastest computer in the world. The problem is that his method first generates all the permutations, then it checks them. The highest-capacity solid-state drive (SSD) on the market is 100 Terabytes (10^14 bytes). Even if we used an efficient encoding scheme (4 bits per entry), it would take 600,000 of those drives to store all the permutations. If it's solvable at all, then you must use iterative methods. The command is Iterator:-Permute. 

@Joe Riel It's ridiculous that one needs to declare _self at all. It's akin to declaring _params, thisproc, thismodule, etc.

@Christian Wolinski You wrote (well after I posted the above Answer):

• Often I lose sessions because STOP button does not accomplish.

You're either ignoring my Answer above, or you don't understand it, or both. If you use your operating system to kill the kernel, then the following things will happen:

• You'll get a pop-up message about a "lost kernel connection". Nearly everything written in that message is either misleading or flat-out wrong. In particular, you don't need to close your Maple session. It's as if that message was written by a legal department or marketing department rather than by someone who actually knows anything about Maple.
• After dismissing that pop-up, you'll be able to save your worksheet exactly as it was at the instant that the kernel was killed (instead of as it was at the most-recent auto-save).
• The above is true regardless of whether you have the auto-save feature turned on.
• Once you're familiar with the steps (find, kill, dismiss, save, exit (worksheet, not session), re-open), this process is often faster than using the STOP button.

@Kitonum I'm amazed that a solution can be found in reasonable time by that method because there are 

(9!/(3!*2!*2!))^6;
                   11948427342082473984000000

(approximately 10^25 or 10 septtillion) possible permutations. I wonder roughly what proportion of them are solutions?