How to broadcast a message to an specific clone?

I am sorry to be a pain with the problems of this small project, I appreciate your patience.

I have a new problem that I don't know how to solve. I would like the click on a number (the black line of a number, not its blue square) to happen the same as if you click on its blue square. That is, it is a clone that has to tell another clone to change its color to white. I can send a message when I click on a "number clone", but how can I make sure that only the "square clone" I have under the mouse (and below the number) is the one that changes its color?


I didn't know the "tell block" and it's interesting, but the underlying problem is telling a clone of a sprite something to do (not just a sprite).
I tried something like this using the tell block, but apparently it does nothing.

Then I realized that I could also use that order with the "broadcast block", but nothing happened either. I can't think of any condition to hide the clone that I have under the number I'm clicking.

If the clone has the same name as the parent, you can't use the name in the TELL block to talk to a specific clone. But you can use a sprite itself, not its name, as the first input to TELL. For example:

That's kind of a silly example, just to make the point that you can drop a sprite-valued expression onto the first input to TELL. What you'd really do, probably, is have each square have a local variable pointing to the corresponding number clone.