Multiple entry in same window

Here's a little demo program in response to this help request on Reddit:

https://www.reddit.com/r/learnprogramming/comments/h884vg/is_there_any_easy_gui_maker_for_python/

The idea is to get an initial value in an input box, then get 3 more values in the same box.

In this implementation you can press the "Enter" button or the return key to enter a value.

The result is put into a single list that is shown at the end.

On Windows it looks like this: