A trapping game for 16K. Your inverse star leaves a trail as it moves; steer it with I (up), M (down), J (left) and K (right), and with no key pressed it keeps moving right. The computer’s player does the same. Run into a trail and you lose; trap the computer and you win. After YOU WIN or YOU LOSE the game starts again.
The playing field is kept in memory above address 30000, so it needs 16K.
Published in Syntax August 1982 (Entrapment).
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Source Code
50 CLEAR
55 CLS
60 LET B=30000
69 FAST
70 FOR L=2 TO 19
71 FOR M=2 TO 30
72 POKE B+L*40+M,CODE (" ")
73 NEXT M
74 NEXT L
80 RAND
110 FOR N=1 TO 31
120 PRINT AT 21,N;"▞"
130 PRINT AT 1,N;"▞"
140 POKE B+21*40+N,CODE ("▞")
150 POKE B+1*40+N,CODE ("▞")
160 NEXT N
170 FOR N=1 TO 21
180 PRINT AT N,1;"▞"
190 PRINT AT N,31;"▞"
200 POKE B+N*40+1,CODE ("▞")
210 POKE B+N*40+31,CODE ("▞")
220 NEXT N
225 SLOW
230 LET A=INT (RND*16+2)
240 LET C=INT (RND*26+2)
250 PRINT AT A,C;"+"
251 POKE B+A*40+C,CODE ("+")
252 LET D=INT (RND*17+2)
253 LET E=INT (RND*26+2)
254 PRINT AT D,E;"*"
255 POKE B+D*40+E,CODE ("*")
256 LET M$=INKEY$
258 IF M$="K" THEN GOTO 510
259 IF M$="I" THEN GOTO 530
260 IF M$="M" THEN GOTO 550
265 IF M$="J" THEN GOTO 490
266 GOTO 510
270 LET C=C+1
272 IF PEEK (B+A*40+C)<>CODE (" ") THEN GOTO 290
273 PRINT AT A,C;"+"
275 POKE B+A*40+C,CODE ("+")
280 GOTO 256
290 LET C=C-1
300 LET C=C-1
305 IF PEEK (B+A*40+C)<>CODE (" ") THEN GOTO 340
310 PRINT AT A,C;"+"
320 POKE B+A*40+C,CODE ("+")
330 GOTO 256
340 LET C=C+1
341 LET A=A+1
344 IF PEEK (B+A*40+C)<>CODE (" ") THEN GOTO 400
355 PRINT AT A,C;"+"
360 POKE B+A*40+C,CODE ("+")
370 GOTO 256
400 LET A=A-1
403 LET A=A-1
405 IF PEEK (B+(A*40)+C)<>CODE (" ") THEN GOTO 450
410 PRINT AT A,C;"+"
420 POKE B+(A*40)+C,CODE ("+")
430 GOTO 256
450 CLS
460 PRINT AT 10,10;"YOU WIN"
461 PAUSE 100
465 GOTO 50
490 LET E=E-1
500 IF PEEK (B+D*40+E)<>CODE (" ") THEN GOTO 700
501 PRINT AT D,E;"*"
502 POKE B+D*40+E,CODE ("*")
503 GOTO 270
510 LET E=E+1
520 IF PEEK (B+D*40+E)<>CODE (" ") THEN GOTO 700
521 POKE B+D*40+E,CODE ("*")
522 PRINT AT D,E;"*"
523 GOTO 270
530 LET D=D-1
540 IF PEEK (B+D*40+E)<>CODE (" ") THEN GOTO 700
541 POKE B+D*40+E,CODE ("*")
545 PRINT AT D,E;"*"
547 GOTO 270
550 LET D=D+1
560 IF PEEK (B+D*40+E)<>CODE (" ") THEN GOTO 700
565 POKE B+D*40+E,CODE ("*")
570 PRINT AT D,E;"*"
575 GOTO 270
700 CLS
705 PRINT AT 10,12;"YOU LOSE"
715 PAUSE 100
720 GOTO 50Note: Type-in program listings on this website use ZMAKEBAS notation for graphics characters.