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Christopher Greaves

Turing Machines

This set of web pages will show you how I went about building and running Turing Machines on an interpreter written in Microsoft Word 2003 Visual Basic for Applications. If you would like to run my demonstrations you will need access to MSWord. Without access to MSWord you can read through the notes and the program code and work through the Turing Machine tables by hand.

You can use the notes to build an interpreter, and hence the set of Turing Machines, in a language of your choice.


I was wandering through my local library in November2014, thinking to pick up some biology books when my eyes were caught by three books about Alan Mortimer Turing. I grabbed them, took them home and read them (and went back for more).

Id heard of Turing first when I worked at ICLs SDC in Adelaide many of us embarked on projects to write language translators. I thought a bit about Turing in the years that I developed and played with a Single Instruction Computer. Playing Diplomacy at SDC led me into the study of the origins of the Third Balkan War, and THAT led me to Winston S. Churchill and THAT led me to Bletchley Park, the Enigma machines, and TADA! - Alan Turing.

Whats not to like, eh?

So I built a genuine Turing machine out of paper.

Christopher Greaves Turing_DSCN0110.JPG

OK. Not genuine; for one thing my paper tape is not infinite.

So there was nothing for it but to develop a Turing Machine. In Microsoft Words Visual Basic for Applications (VBA).

Web Pages

References to books I consulted. I recommend that you pick two and skim through them.

Table of Versions as I progressed. These notes are a tutorial. You can treat each numbered step as a lesson in developing Turing Machines. My choice of topics began with arithmetic on decimal numbers, wandered into worked examples from the books Id read, and at this time is plodding its way through Multiplication and Division in Roman Numerals.

My current WhatFAQ summarizes some of the problems I encountered in building and running the interpreter, and some of the steps I took to resolve issues

The Auxiliary Notes contain essays on specific areas that were too broad to introduce as a topic. I suggest you peruse the titles so that you will know that there is background material when you enter a new topic.

Have fun!


416-993-4953 CPRGreaves@gmail.com

Toronto, Thursday, March 31, 2016 1:36 PM

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