Execution flow control (pause/restart)

[koffrig]

I am trying to implement the game of life in a Tkinter GUI with python.
Here is an example of what I am trying to achieve: http://www.math.com/students/wonders/life/life.html (the java applet in particular)
The question is quite basic, just as my background in python and programming in general.
The effect that I am trying to achieve is pause/play control of execution of a certain algorithm.
In other words, I want to have debugger-like control of my program, where at any certain point of time i can interrupt a loop or a process, stop it, change some values in its directives and then resume it.
I have been looking into threads, but they appear to be intended for resource sharing rather than controlling the flow of execution.
Could anyone direct me to a place to start, or suggest a technique that would visibly produce a similar result.
Layman terms and full sentences please.
All input is appreciated.
Ivan K

[TrustyTony]

You could divide the job in small enough pieces and check for parameter change and pause after each piece. You should separate parameter entering in separate thread so it stays active during execution.