American Embassy School Grade 9 student Manit developed the classic Tic Tac Toe game in *Terrapin Logo* as a contest between the computer and a human player. The person goes first, clicking on a square to mark it with an X. The computer follows playing the O role. Manit has programmed the computer to be a clever Tic Tac Toe player and hard to beat.

This program utilizes basic artificial intelligence in Terrapin Logo to provide the computer strategy. Classic turtle graphics are used to draw the Tic Tac Toe board. Interaction is achieved by reading the mouse location and button status.

Manit explains the testing procedures used in developing the program.

I ran several tests on this game, first I played like a novice and saw if the computer could actually win, this test proved to be successful. Then gradually I improved my level of play and saw whether the computer could block of corner tricks etc.

Another test I ran was I played each square and saw whether the computer would play the square it was supposed to, this was tedious but it was a must I also tested for the clicking function. This proved to me a major head ache because I had changed the origin so it proved to be a bit tricky as the co-ordinates of the board and mouse were different. In the end it worked out.

Start Terrapin Logo, and load them into workspace or into an editor and use Edit/Define to define them into workspace. Alternately, open an editor, and paste the procedures into the editor. Then define the procedures with Edit/Define. Type TICTACTOE to begin and see if you can beat the strategy Manit developed for the computer player!

- TicTacToe.lgo
TO CLICK1 PU SETXY MOUSE IF (AND (AND 50 <= XCOR XCOR <= 150) (AND -50 <= YCOR YCOR <= 50)) [DRAW.X] IF (AND (AND -50 <= XCOR XCOR <= 50) (AND 50 <= YCOR YCOR <= 150)) [DRAW.X11] IF (AND (AND 50 <= XCOR XCOR <= 150) (AND 50 <= YCOR YCOR <= 150)) [DRAW.X12] IF (AND (AND 150 <= XCOR XCOR <= 250) (AND 50 <= YCOR YCOR <= 150)) [DRAW.X13] IF (AND (AND -50 <= XCOR XCOR <= 50) (AND -50 <= YCOR YCOR <= 50)) [DRAW.X01] IF (AND (AND 150 <= XCOR XCOR <= 250) (AND -50 <= YCOR YCOR <= 50)) [DRAW.X03] IF (AND (AND -50 <= XCOR XCOR <= 50) (AND -150 <= YCOR YCOR <= -50)) [DRAW.XB1] IF (AND (AND 50 <= XCOR XCOR <= 150) (AND -150 <= YCOR YCOR <= -50)) [DRAW.XB2] IF (AND (AND 150 <= XCOR XCOR <= 250) (AND -150 <= YCOR YCOR <= -50)) [DRAW.XB3] END TO POINT IF BUTTON? [PU SETXY MOUSE PD STOP] POINT END TO GETTIME PU SETXY [300 100] HT PD SETPC 0 MAKE "T TIME SETFONT "TIME 14 1 TT :T WAIT 1000 SETPC 15 (STAMPOVAL 100 30 "TRUE) GETTIME END TO O11 MAKE "A1 "2 MAKE "CM "0 PU SETPOS [-50 100] PD STAMPOVAL 50 50 END TO O12 MAKE "A2 "2 MAKE "CM "0 PU SETPOS [50 100] PD STAMPOVAL 50 50 END TO O21 MAKE "A4 "2 MAKE "CM "0 PU SETPOS [-50 0] PD STAMPOVAL 50 50 END TO O13 MAKE "A3 "2 MAKE "CM "0 PU SETPOS [150 100] PD STAMPOVAL 50 50 PD END TO O23 MAKE "A6 "2 MAKE "CM "0 PU SETPOS [150 0] PD STAMPOVAL 50 50 END TO O31 MAKE "A7 "2 MAKE "CM "0 PU SETPOS [-50 -100] PD STAMPOVAL 50 50 END TO O32 MAKE "A8 "2 MAKE "CM "0 PU SETPOS [50 -100] PD STAMPOVAL 50 50 END TO O33 MAKE "A9 "2 MAKE "CM "0 PU SETPOS [150 -100] PD STAMPOVAL 50 50 END TO CHECKSQUARE CLEARTEXT IF :A1 = 1 THEN PR [SQUARE 1] IF :A2 = 1 THEN PR [SQUARE 2] IF :A3 = 1 THEN PR [SQUARE 3] IF :A4 = 1 THEN PR [SQUARE 4] IF :A5 = 1 THEN PR [SQUARE 5] IF :A6 = 1 THEN PR [SQUARE 6] IF :A7 = 1 THEN PR [SQUARE 7] IF :A8 = 1 THEN PR [SQUARE 8] IF :A9 = 1 THEN PR [SQUARE 9] END TO DRAW.O PU SETPOS [51 0] PD STAMPOVAL 50 50 END TO DRAW.X PU SETPOS [50 0] PD SETHEADING 45 FD 70 BK 140 SETPOS [51 0] LT 90 FD 70 BK 140 MAKE "A5 "1 END TO RESETBOARD MAKE "A1 "0 MAKE "A2 "0 MAKE "A3 "0 MAKE "A4 "0 MAKE "A5 "0 MAKE "A6 "0 MAKE "A7 "0 MAKE "A8 "0 MAKE "A9 "0 END TO SHOWRESULT PR [WHAT IS GOING ON?? ! YOU HAVE BEEN BEATEN ME ! !] TOPLEVEL END TO BOARD HT CS SETBG "YELLOW PU SETORIGIN [50 0] HOME PD FD 150 BK 150 BK 150 FD 150 BK 50 LT 90 FD 100 BK 100 RT 90 FD 100 RT 90 RT 180 FD 100 BK 200 RT 90 FD 100 BK 300 FD 100 LT 90 RT 180 FD 100 BK 200 FD 100 BK 100 LT 90 FD 100 RT 90 FD 200 PU SETPOS [-540 150] PD SETFONT "TIMES 14 1 SETPC "BLACK TT [YOU ARE NOW FACING THE IMPOSSIBLE] PU HOME CLEARTEXT RESETBOARD MAKEMOVE WAIT 200 COMPUTERSMOVE MAKEMOVE WAIT 200 COMPUTERSMOVE MAKEMOVE WAIT 200 COMPUTERSMOVE MAKEMOVE WAIT 200 COMPUTERSMOVE MAKEMOVE WAIT 200 COMPUTERSMOVE MAKEMOVE END TO CLICK PU SETXY MOUSE IF (AND (AND 50 <= XCOR XCOR <= 150) (AND -50 <= YCOR YCOR <= 50)) [DRAW.X] IF (AND (AND -50 <= XCOR XCOR <= 50) (AND 50 <= YCOR YCOR <= 150)) [DRAW.X11] IF (AND (AND 50 <= XCOR XCOR <= 150) (AND 50 <= YCOR YCOR <= 150)) [DRAW.X12] IF (AND (AND 150 <= XCOR XCOR <= 250) (AND 50 <= YCOR YCOR <= 150)) [DRAW.X13] IF (AND (AND -50 <= XCOR XCOR <= 50) (AND -50 <= YCOR YCOR <= 50)) [DRAW.X01] IF (AND (AND 150 <= XCOR XCOR <= 250) (AND -50 <= YCOR YCOR <= 50)) [DRAW.X03] IF (AND (AND -50 <= XCOR XCOR <= 50) (AND -150 <= YCOR YCOR <= -50)) [DRAW.XB1] IF (AND (AND 50 <= XCOR XCOR <= 150) (AND -150 <= YCOR YCOR <= -50)) [DRAW.XB2] IF (AND (AND 150 <= XCOR XCOR <= 250) (AND -150 <= YCOR YCOR <= -50)) [DRAW.XB3] END TO COMPUTERSMOVE MAKE "CM "1 IF (AND (AND :A1 = 2 :A2 = 2) (AND :A3 = 0 :CM = 1)) [O13] IF (AND (AND :A1 = 2 :A2 = 0) (AND :A3 = 2 :CM = 1)) [O12] IF (AND (AND :A1 = 0 :A2 = 2) (AND :A3 = 2 :CM = 1)) [O11] IF (AND (AND :A4 = 2 :A5 = 2) (AND :A6 = 0 :CM = 1)) [O23] IF (AND (AND :A4 = 2 :A5 = 0) (AND :A6 = 2 :CM = 1)) [OCENTRE] IF (AND (AND :A4 = 0 :A5 = 1) (AND :A6 = 2) :CM = 1) [O21] IF (AND (AND :A7 = 2 :A8 = 2) (AND :A9 = 0 :CM = 1)) [O33] IF (AND (AND :A7 = 2 :A7 = 0) (AND :A9 = 2 :CM = 1)) [O32] IF (AND (AND :A7 = 0 :A8 = 2) (AND :A9 = 2 :CM = 1)) [O31] IF (AND (AND :A1 = 0 :A4 = 2) (AND :A7 = 2 :CM = 1)) [O11] IF (AND (AND :A1 = 2 :A4 = 2) (AND :A7 = 0 :CM = 1)) [O31] IF (AND (AND :A1 = 2 :A4 = 2) (AND :A7 = 0 :CM = 1)) [O21] IF (AND (AND :A2 = 0 :A5 = 2) (AND :A8 = 2 :CM = 1)) [O12] IF (AND (AND :A2 = 2 :A5 = 0) (AND :A8 = 2 :CM = 1)) [OCENTRE] IF (AND (AND :A2 = 2 :A5 = 2) (AND :A8 = 0 :CM = 1)) [O32] IF (AND (AND :A3 = 0 :A6 = 2) (AND :A9 = 2 :CM = 1)) [O13] IF (AND (AND :A3 = 2 :A6 = 0) (AND :A9 = 2 :CM = 1)) [O23] IF (AND (AND :A3 = 2 :A6 = 2) (AND :A9 = 0 :CM = 1)) [O33] IF (AND (AND :A1 = 0 :A5 = 2) (AND :A9 = 2 :CM = 1)) [O11] IF (AND (AND :A1 = 2 :A5 = 0) (AND :A9 = 2 :CM = 1)) [OCENTRE] IF (AND (AND :A1 = 2 :A5 = 2) (AND :A9 = 0 :CM = 1)) [O33] IF (AND (AND :A3 = 0 :A5 = 2) (AND :A7 = 2 :CM = 1)) [O13] IF (AND (AND :A3 = 2 :A5 = 0) (AND :A7 = 2 :CM = 1)) [OCENTRE] IF (AND (AND :A3 = 2 :A5 = 2) (AND :A7 = 0 :CM = 1)) [O31] IF (AND (AND :A1 = 1 :A2 = 1) (AND :A3 = 0 :CM = 1)) [O13] IF (AND (AND :A1 = 1 :A2 = 0) (AND :A3 = 1 :CM = 1)) [O12] IF (AND (AND :A1 = 0 :A2 = 1) (AND :A3 = 1 :CM = 1)) [O11] IF (AND (AND :A4 = 1 :A5 = 1) (AND :A6 = 0 :CM = 1)) [O23] IF (AND (AND :A4 = 1 :A5 = 0) (AND :A6 = 1 :CM = 1)) [OCENTRE] IF (AND (AND :A4 = 0 :A5 = 1) (AND :A6 = 1) :CM = 1) [O21] IF (AND (AND :A7 = 1 :A8 = 1) (AND :A9 = 0 :CM = 1)) [O33] IF (AND (AND :A7 = 1 :A7 = 0) (AND :A9 = 1 :CM = 1)) [O32] IF (AND (AND :A7 = 0 :A8 = 1) (AND :A9 = 1 :CM = 1)) [O31] IF (AND (AND :A1 = 0 :A4 = 1) (AND :A7 = 1 :CM = 1)) [O11] IF (AND (AND :A1 = 1 :A4 = 0) (AND :A7 = 1 :CM = 1)) [O21] IF (AND (AND :A1 = 1 :A4 = 1) (AND :A7 = 0 :CM = 1)) [O31] IF (AND (AND :A2 = 0 :A5 = 1) (AND :A8 = 1 :CM = 1)) [O12] IF (AND (AND :A2 = 1 :A5 = 0) (AND :A8 = 1 :CM = 1)) [OCENTRE] IF (AND (AND :A2 = 1 :A5 = 1) (AND :A8 = 0 :CM = 1)) [O32] IF (AND (AND :A3 = 0 :A6 = 1) (AND :A9 = 1 :CM = 1)) [O13] IF (AND (AND :A3 = 1 :A6 = 0) (AND :A9 = 1 :CM = 1)) [O23] IF (AND (AND :A3 = 1 :A6 = 1) (AND :A9 = 0 :CM = 1)) [O33] IF (AND (AND :A1 = 0 :A5 = 1) (AND :A9 = 1 :CM = 1)) [O11] IF (AND (AND :A1 = 1 :A5 = 0) (AND :A9 = 1 :CM = 1)) [OCENTRE] IF (AND (AND :A5 = 1 :A5 = 1) (AND :A9 = 0 :CM = 1)) [O33] IF (AND (AND :A3 = 0 :A5 = 1) (AND :A7 = 1 :CM = 1)) [O13] IF (AND (AND :A3 = 1 :A5 = 0) (AND :A7 = 1 :CM = 1)) [OCENTRE] IF (AND (AND :A3 = 1 :A5 = 1) (AND :A7 = 0 :CM = 1)) [O31] IF (AND :A5 = 0 :CM = 1) [OCENTRE] IF (AND (AND :A1 = 1 :A9 = 1) (AND :A2 = 0 :CM = 1)) [O12] IF (AND (AND :A1 = 1 :A9 = 1) (AND :A4 = 0 :CM = 1)) [O21] IF (AND (AND :A1 = 1 :A9 = 1) (AND :A6 = 0 :CM = 1)) [O23] IF (AND (AND :A1 = 1 :A9 = 1) (AND :A8 = 0 :CM = 1)) [O32] IF (AND (AND :A3 = 1 :A7 = 1) (AND :A2 = 0 :CM = 1)) [O12] IF (AND (AND :A3 = 1 :A7 = 1) (AND :A4 = 0 :CM = 1)) [O21] IF (AND (AND :A3 = 1 :A7 = 1) (AND :A6 = 0 :CM = 1)) [O23] IF (AND (AND :A3 = 1 :A7 = 1) (AND :A8 = 0 :CM = 1)) [O32] IF (AND :A1 = 0 :CM = 1) [O11] IF (AND :A3 = 0 :CM = 1) [O13] IF (AND :A7 = 0 :CM = 1) [O31] IF (AND :A9 = 0 :CM = 1) [O33] IF (AND :A2 = 0 :CM = 1) [O12] IF (AND :A4 = 0 :CM = 1) [O21] IF (AND :A6 = 0 :CM = 1) [O24] IF (AND :A8 = 0 :CM = 1) [O32] IF (:CM = 1) [RESULTDRAW] END TO SELECT.ICON POINT WAIT 50 CLICK END TO TC CS PU FD 100 SETPC 12 PD (STAMPOVAL 20 20 "TRUE) PU HOME MOVECONTROL END TO DRAW.X01 PU SETPOS [0 50] PD SETHEADING 225 FD 140 BK 70 RT 90 FD 70 BK 140 MAKE "A4 "1 END TO MOVECONTROL MAKE "K RC IF :K = CHAR 193 FD 5 IF :K = CHAR 194 BK 5 IF :K = "Q [PR [OVER] WAIT CS STOP] IF :K = CHAR 196 RT 10 IF :K = CHAR 195 LT 10 MAKE "C BASECOLOR (DOTCOLOR) IF :C = 12 [PR [COLLISION] HOME SETPC "BLACK STOP] MOVECONTROL END TO DRAW.X03 MAKE "A6 "1 PU SETPOS [100 50] PD SETHEADING 135 FD 140 BK 70 LT 90 FD 70 BK 140 END TO DRAW.X11 MAKE "A1 "1 PU SETPOS [0 50] SETHEADING 0 PD LT 45 FD 140 BK 70 RT 90 FD 70 BK 140 END TO DRAW.X12 MAKE "A2 "1 PU SETPOS [0 50] SETHEADING 90 PD LT 45 FD 140 BK 70 RT 90 FD 70 BK 140 END TO MAKEMOVE CHECKRESULT SELECT.ICON CHECKSQUARE END TO DRAW.X13 MAKE "A3 "1 PU SETPOS [100 50] PD SETHEADING 45 FD 140 BK 70 RT 90 FD 70 BK 140 END TO OCENTRE MAKE "A5 "2 MAKE "CM "0 PU SETPOS [50 0] PD STAMPOVAL 50 50 END TO DRAW.XB1 PU MAKE "A7 "1 SETPOS [0 -50] PD SETHEADING 225 FD 140 BK 70 RT 90 FD 70 BK 140 END TO DRAW.XB2 MAKE "A8 "1 PU SETPOS [0 -50] SETHEADING 135 PD FD 140 BK 70 LT 90 FD 70 BK 140 END TO DRAW.XB3 MAKE "A9 "1 PU SETPOS [100 -50] SETHEADING 135 PD FD 140 BK 70 LT 90 FD 70 BK 140 END TO CHECKRESULT IF (AND (AND :A1 = 1 :A2 = 1) (:A3 = 1)) [SHOWRESULT] IF (AND (AND :A4 = 1 :A5 = 1) (:A6 = 1)) [SHOWRESULT] IF (AND (AND :A7 = 1 :A8 = 1) (:A9 = 1)) [SHOWRESULT] IF (AND (AND :A1 = 1 :A4 = 1) (:A7 = 1)) [SHOWRESULT] IF (AND (AND :A2 = 1 :A5 = 1) (:A8 = 1)) [SHOWRESULT] IF (AND (AND :A3 = 1 :A6 = 1) (:A9 = 1)) [SHOWRESULT] IF (AND (AND :A1 = 1 :A5 = 1) (:A9 = 1)) [SHOWRESULT] IF (AND (AND :A3 = 1 :A5 = 1) (:A7 = 1)) [SHOWRESULT] IF (AND (AND :A1 = 2 :A2 = 2) (:A3 = 2)) [SHOWLIKELYRESULT] IF (AND (AND :A4 = 2 :A5 = 2) (:A6 = 2)) [SHOWLIKELYRESULT] IF (AND (AND :A7 = 2 :A8 = 2) (:A9 = 2)) [SHOWLIKELYRESULT] IF (AND (AND :A1 = 2 :A4 = 2) (:A7 = 2)) [SHOWLIKELYRESULT] IF (AND (AND :A2 = 2 :A5 = 2) (:A8 = 2)) [SHOWLIKELYRESULT] IF (AND (AND :A3 = 2 :A6 = 2) (:A9 = 2)) [SHOWLIKELYRESULT] IF (AND (AND :A1 = 2 :A5 = 2) (:A9 = 2)) [SHOWLIKELYRESULT] IF (AND (AND :A3 = 2 :A5 = 2) (:A7 = 2)) [SHOWLIKELYRESULT] END TO TICTACTOE CS SETBG "GREEN PU SETPOS [-100 100] PD SETFONT "TIMES 32 1 SETPC "WHITE TT [TIC TAC TOE] PU SETPOS [-175 50] SETPC "BLACK PD TT [BY MANIT BHARANY] PU SETPOS [-350 0] PD SETFONT "TIMES 14 1 SETPC "AQUA TT [1. IT IS A ONE PLAYER GAME 2. PLACE YOUR BET AT THE START GAME] PU SETPOS [-530 -25] PD SETFONT "TIMES 13 1 TT [3. IF YOU WIN YOU DOUBLE YOUR MONEY, IF YOU LOSE YOU LOSE YOUR MONEY AND IF YOU DRAW YOU GET YOUR MONEY BACK] PU SETPOS [-560 -50] PD TT [4.THE PLAYER ALWAYS STARTS FIRST,THEN THE COMPUTER,THEN THE PLAYER AND SO ON.IN OTHER WORDS TAKE TURNS ALTERNATELY] PU SETPOS [-425 -75] PD TT [5. YOU CAN PLACE YOUR SHAPE ANYWHERE ON THE GRID AS LONG AS THE SQUARE IS NOT OCCUPIED] PU SETPOS [-375 -100] PD TT [6. THE GAME IS WON IF EITHER THE COMPUTER OR THE PLAYER FORMS A STRAIGHT LINE] PU SETPOS [-275 -125] PD TT [IF NONE MANAGE TO DO SO THE GAME IS DEEMED TO BE A DRAW.] PU SETPOS [-125 -175] PD SETFONT "TIMES 26 1 SETPC "BLACK TT [HIT X TO BEGIN] LABEL "START MAKE "BEGIN RC IF :BEGIN = "X BOARD GO "START END TO SHOWLIKELYRESULT PR [HEH HEH HEH WHAT IS GOING ON?? ! YOU HAVE BEEN BEATEN ! !] TOPLEVEL END TO RESULTDRAW PR [THIS MATCH ENDS IN A DRAW] TOPLEVEL END MAKE "C "0 MAKE "K "Q MAKE "T [13 44 14] MAKE "BEGIN "X MAKE "A1 "1 MAKE "A2 "1 MAKE "A3 "2 MAKE "A4 "2 MAKE "A5 "1 MAKE "A6 "1 MAKE "A7 "1 MAKE "A8 "2 MAKE "A9 "2 MAKE "CM "1 MAKE "|A1"| "0

- Procedure:
- TICTACTOE
- Description:
- Play Tic Tac Toe against the computer
- Level:
- Intermediate
- Compatible:
- Logo 3, Logo 4
- Tags:
- Game, Tic Tac Toe