JOURNAL
OF TIlE

FRANKLIN I N S T I T U T E
OF T H E STATE OF P E N N S Y L V A N I A ,

FOR THE PRO]~[OTION OF THE MECItANIC ARTS.
¥o~. CVlI.

JANUARY,

1879.

No. 1.

THE Franklin Institute is not responsible, as a body, for the statements and
opinions advanced by contributors to the Jo~nSAL.
AN AUTOMATIC

TIT-TAT-TO

MACHINE.*

FRA%K T. FREELAND,
University of Pennsylvania, Class of 1~79.
The p r o b l e m of designing a machine which would p l a y one of the
games of skill, has been a t t e m p t e d m a n y times. S e v e r a l a u t o m a t a
have been c o n s t r u c t e d which would p l a y the game of chess ; but it
was always found upon investigation, t h a t their motions were controlled b y a hidden confederate. The infinite number of v a r i a t i o n s
in chess r e n d e r s the c o n s t r u c t i o n of a true chess a u t o m a t o n impossible. Mr. B a b b a g e , the i n v e n t o r of the difference engine, in his
n i n t h B r i d g e w a t e r treatise, refers to the possibility of c o n s t r u c t i n g
an automaton which would p l a y a much simpler game, t h a t of
tit-tat-to. A g e n t l e m a n of this city has i n v e n t e d and made some
d r a w i n g s of such an automaton, w o r k i n g upon the p r i n c i p l e of a
-x'UNIvERSITY OF ])I~NNA., ])HILA., z~5)~ember 9lb. 1S7S.

iland you herewith, description and drawings of the automatic
Tit-Tat-To Player, exhibited at your last meeting. The invcnti.n displays so much
mechanical genius that it cannot hut prove of interest, and perhaps of service, to all
mechanicians.
Respectfully,
W.~. D. MAal(s.
De:tr Sir : - - I

To J. B. KNIGHT, ESQ., Secretary F r a n k l i n Institute.

WHOLE 1gO. VOL CVH.--(TglRD SERIES,Vol. lxxvii.)

1

Freeland-- Tit- Tat- To Machine.

[Jour.F r a n k . Inst.,

movable Jacquard loom card. The machine herein described works
upon an entirely different principle, that of a mechanical table, which
contains all the possible variations of the game.
LOWER

PLAN.

I!

r

I

Di iL
~i:

~
o

WI

llJqliilpppl
e; l

K

_

~____

J

o

~

N

T,t,,t

The game of tit-tat-to is played by two persons. A double cross
is drawn upon a sheet of paper. One of the players chooses a cross
11213
(X) for his mark, and writes it in one of the spaces 1-9.
4 5 6
The other player chooses a zero (0), and writes it in one
of the remaining spaces, and so on alternately. The
7 - 8- 9- game is won by tile player who first succeeds in getting
three of his marks in a row. I f the spaces are all filled before
either player gets a row, the game is drawn.
The following is an exhaustive analysis of the game of tit-tat-to,
for a machine to play the game, under the conditions that the

Jan., 1879.]

Freeland-- Tit- Tat- To Machine.

3

machine shall always play the best move; and that when the
opponent, during the first three moves of each game, wishes to play
one of two or four symmetrical moves, he shall take the one having
the lowest number.
THE OPPONENT BEGINS.
[These games will be found upon the Surface of the .Cylinder, lines 1 - - 7 4 inclusive.]
THE MACHINE BEGINS.
0

X

0

X

1

2

5

9

°Ix
j

3

34678
7

5

25689
2

........

0

[

X

RBS.

i0

7

3

345
4
268
7

7
8
4
3

4

0
0
0
0
0
0

6
0
0
0
2

8

2

5

6

4

9

23589
2

1

45678
8

4

34679
3

5

56789
3

7

46789
3

3
5

8

45689
3

9

1

2

45679
8

5
4
7

3
7

34679
9

8

34678

9

4

289

7
9
3

4
568

5
4

3
469

6
3

9
678

8
9

4

6

689

4

9
468

8
,)

5

7

467

5

3

6

469

3

365

7
6

0
0
0
0
0
0
0
0

4
0
0
0
0
0
8
9
0
0
0
0
0
4
6

0
0
0
0
0
0
0
0

0

4

Freeland-- Tit- Tat- To Machine.

[Jour.F,'a,,k. rnst.,

The method oF transforming this symbolic table into a meehanioal
one, will be obtained by a comparison of it with the Surface of the
63jlinder, beginning at line 75. There are one hundred and fifty
lines upon the cylinder. The omitted ones may be obtained from the
latter part of the above table. Our 1st, 2d, 3d and 4th moves in any
game are set down in the columns T I, II, I I I and IV. Each column contains nine vertical lines. The figure ] is represented by a
pin upon the first line; 2, by a pin upon the second line, etc. The
machine's answering moves are set down in the column U, upon the
same horizontal line as ours. Whenever its move gives it three in a
row, another pin is put upon the line U0. The row of pins Ux
affords a hold to a catch. When the machine begins, its first move
is set down in the column S.
DESCRIPTIO~.~In the Lower .Plan, the cylinder D is represented,
its surface being prepared as described
above. The cord, weight
~EcTION
S.
and pulley p, give it a tendency
to turn toward us. In front of it
are the two cross-beams or ways
W W. On them the carriage I
runs. The cord P , running over
a pulley to a weight, gives the
carriage a tendency to move to
the right. The carriage has a
catch C~ which engages with four
pins set in a groove in one of the
ways. Whenever the catch C is
pushed, the carriage 2-moves a
space to the right, equal to one
column of the table. The wire 0
is to draw it back to its first position. On the carriage are nine
sliders, T 1-9. When they move
forward, they engage with the
pins upon the cylinder. T 1 , 2
and 5 have the pins Z 1, 2 and 5
in them, which project below the
carriage.
A platform is secured to the ways at the left. On it are the

Jan., 1879.]

Freeland-- Tit- Tat- To Machine.

5

sliders S 1, 2 and 5, having in them the pins Q 1, 2 and 5, which
project below the platform. Supported on a bracket, under the
platform, are the flat, horizontal cams Y 1, 2 and 5. When the
carriage is in its first position, the pins Q 1, 2, 5 and Z 1, 2, 5 engage
with these cams. They are of such a shape, that when the slider T
1, 2 or 5 moves backward, the pin Z 1, 2 or 5 rubs over the pointed
end of the cam Y 1, 2 or 5, and so pushes S 1, 2 or 5 forward.
At the right is secured to the ways a platform, on which are the
sliders Ux, 1-9, 0. The slider U~, by engaging with the row of
UPPER
~a~elto..

, .t

PLAN.

, , ~z, , . : ~ , , , ~*, , , t ~ l a c h e s . o

pins Ux, locks the cylinder. U 1-9 discover the answering move.
U0 determines the striking of the bell. These sliders are set at a
higher level than the others, so that when they move forward, they
impinge upon the pins, instead of going under them. K i s a horizontal lever, pivoted at its centre. S 1, 2, 5 and Ux have in their
ends bent wires, M a n d N, so that when S 1, 2 or 5 moves forward,
K pulls Ux backward. J is a vertical leaf, pivoted at its lower

6

Freeland-- Tit- Tat- To Machine.

[ao,r. Frank. Inst.,

corners, and connected by a double bell-crank with the lever H 1, as
shown in Section S. When H 1 is pushed forward, J d r a w s out the
catch Ux and the sliders S 1, 2 and 5. q is a vertical leaf, pivoted
at its lower corners. When it moves toward the cylinder, it releases
the carriage by striking the catch C. q has secured to it an arm
with a pin in it, as shown at V, Section ~£
SECTION

SEC'

T.

I~)N U.

.?iX

I

"~&t

In the Upper _Plan, is shown a portion of the board. I t has nine
openings in it. Under them move the ares A 1-9. There is a cross
(X) on one end of each, and a zero (0) on the other. These arcs
are secured to the vertical leaves L 1-9, which are pivoted at their
upper corners. B y long wire teeth they gear into the sliders T 1-9
in such a way, that they do not get out of gear when the carriage
moves to the right or left. See the Elevation and ~ection T.
In Section U, the levers Z r 2 and ab are represented. They are
pivoted on each side of the platform at b, and firmly united by a

.Freelandw Tit Tat- To Machine.

Jan., 1879.]

cross-piece under the platform. On the lower end of ab is fastened
an inclined plate V. When the lever H 2 moves backward, the
plate V lifts the arm of ~ by the pin on it, and so releases the
carriage. From ab to H 2 at the point a runs a stout wire. On
it are strung the vertical levers Xx, 1-9, 0. Their upper ends are
held back against the plate F, which serves as a fulcrum, by the

H

EL~-~-~ON.
m

R

A
7

8

9

IIIIII

L
9

.
.
11 I,,I

I(

/

.

.

.

.

|

.

"'

L ...........

,

'
_~ . . . . . . . .

I I~
L~

L

f
I
J

iI [i J
,,

_~ . . . . . . . . . . . .

"

............
1

ii

, •

J

I

I

I

i

ql
/
I

J__, . . . . . . . . .

,11
--

,,

III

:I : I

Ill
:I ! J

~.&l.

springs as shown. Their lower ends are geared into the sliders Ux,
1-9, 0. When H 2, containing the point a, moves forward, the
levers Xx, 1-9, 0 move forward, their upper ends being their fulcrums, pushing ihe sliders Ux, 1-9, 0 forward. If one of these
impinges on a pin, it stops, and becomes the fulcrum of the X belonging to it. Then the upper end of that X goes forward, elongating
the spring. The slider Ux has a slot at its point of gearing, so that
when it is carried forward it is left there. When the upper ends of

Freelan d - - Tit- Tat- To Machine.

[Jour.Frank. Inst.,

X 1-9 move forward, they strike the r o d s / ~ 1-9, which are hooked
to the vertical leaves B 1-9, pivoted at their lower corners. These
are connected by the wire links E 1-9 with the arcs. When the
upper end of X 0 goes forward, it causes a bell to strike.

OeERATI0~.--The machine is wound up by setting all the arcs at
their middle position, so that neither mark appears; then push H 1
and wind up the cylinder by a key at the left; push H 2 and it is
locked ; and lastly draw the carriage into its first position.
We make our move by putting an instrument like an awl into one
of the holes of the arcs, and so moving it that the cross appears.
Suppose we move 2, then slider T 2 goes forward. Release the cylinder from the catch by pushing H 1. The cylinder turns until the
pin at T I 2, line 22, strikes the slider. On pushing H 2 forward,

Jan., l s ~ 9 . ]

Freeland-- Tit- Tat- To Machine.

9

the pin at U 5 will stop the slider U 5, and X 5 will push R 5 and
B 5 forward. Then the w i r e E 5 from B 5 t o A 5 will so move the
are that the zero (0) will appear at the opening 5. At the same
time the slider Ux will move forward and lock
× ×io
the cylinder. When H 2 comesback, the car- - - ! ~ - riage will move into position II, opposite the - - - - i - column T II. Suppose we then move 1, the
!
oiX 0
c y l i n d e r w i l l s t o p a t l i n e 2 8 , and the machine
X Xi 0
....
moves 8, the carriage taking position III. If O OO__
we now move 7, the cylinder will stop at line
24, the machine moves 4, and the carriage x ! O - - X X 0 takes position IV. If we move 6, the cylinder
X X/0
~- ~- ~
stops at line 25, and the machine moves 8. [If -0-]-6-~ ~- - we had moved 8 or 9, the cylinder would have -X -0- - stopped at line 26, the machine would have
moved 6 and won. The pin on U0 causing the bell to strike.] Finally
we move 9, and the game is drawn. The machine is thenwound up.
If we wish the machine to begin, we move one of the arcs so that
the zero appears. Suppose that we so move 1. The slider T 1 is
moved backward, hence S 1 is pushed forward by :Y 1, and K pulls
the catch from the cylinder, which turns until the pin at S 1, line 75,
strikes the slider S 1. Then we make our move, suppose it to be 2.
On touching H 1, the cylinder remains at line 75, and on pushing H 2,
position II. Now, if we move 9, the cylinder
stops at line 76, and the machine moves 7, the
carriage taking position III. If we then move
0 X 0 4, the cylinder stops at line 77, the machine
0 X1X
-~]~-moves 3 and wins, the bell proclaiming the -0-i-0-fact; but, if we move 8, 6 or 87 the cylinder
stops at line 79, the machine moves 4. So it O - I - - wins in either case.
This machine, the first one ever constructed, was built in the
summer of 1878, and exhibited at the Franklin Institute, October
16, 1878. It is now at the University of Pennsylvania, where, since
its final adjustment, it has played a large number of games without
losing a single one.

PtIILADELPHIA,November 8tit, 1878.