A file containing a TM description must obey the following specifications.

1. • an ## begins a comment
   

2. • each line must have the elements separated by TABs (\t)
   

3. • the first line, not a comment, must have the following elements:
   

initial state,  final state, blank and wild-card. Note that the wildcard is not part of a

  standard TM definition, but a shortcut for writing a set of transitions:

 

1. •  (state1,wildcard,state2,wildcard,inst) for every symbol not having other  transition from state1, change to state state2, write the same symbol and move the head according to inst.
   

2. • (state1,wildcard,state2,symbol1,inst) the same as before, except that write symbol1 instead.
   

3. •   each following line represents a transition: a state, a symbol, a new state, a new symbol, a movement (instruction). A movement can be  R or L. Note that each tape symbol must be only represented by a character. Each transition can be followed by a comment (## not needed).
   

The following  example can be found here.

## Accepts a^n^2

##  Rogério Reis 1998

## initial state final state  blank wild-card

0       100     .       *

## Transitions

0       .       100     .       R       epsilon rules!

0       a       1       a       R      

1       *       1       *       R       go to the end

1       .       2       c       L       and there a 'c'                     

2       *       2       *       L       go to the begining

2       B       2       b       L       for a fresh comparision

2       C       2       c       L      

2       A       2       a       L      

2       .       3       .       R      

3       A       3       A       R       one 'a'->'A'

3       a       4       A       R

4       *       4       *       R       now one 'c'->'C'

4       c       5       C       L       or 'b'->'B'

4       b       5       B       L

4       .       20      .       L       next square

5       .       6       .       R       to the begining

5       A       6       A       R

5       *       5       *       L

6       a       4       A       R       'a'->'A'

6       c       90      c       L       if a 'c' or 'b' found fail

6       b       90      b       L

6       .       100     .       L       matches!

6       *       6       *       R

##      (n+1)^2 = n^2 + 2n + 1

## one copy

20      *       20      *       L       find first 'a' or 'A'

20      a       23      a       R

20      A       23      A       R

23      C       24      D       R

23      D       23      D       R

23      *       30      *       L       do another copy

24      .       20      B       L

24      *       24      *       R

## another copy

30      A       31      A       R

30      a       31      a       R

30      *       30      *       L

31      D       32      E       R

31      E       31      E       R

31      B       35      B       R

32      .       30      B       L

32      *       32      *       R

35      *       35      *       R

35      .       36      b       L

## plus 1

36      B       36      b       L

36      E       37      E       R

37      b       38      c       L

38      E       38      c       L

38      *       2       *       L 

\

A file containing a tape must contain a sequence of symbols separated by blanks. An example can be found here.