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A simple mnemonic puzzle game in 10 lines of BASIC MSX
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PazBAS is a simple mnemonic puzzle game in 10 lines of BASIC MSX.


Game Logic

Player must find the character that repeats X times in the matrix.

Above the letters matrix there is the hint message for the character to guess:

  • 1X: indicates a character that appears once
  • 2X: indicates a character that appears twice
  • 3X: indicates a character that appears three times

The time is limited to 10 seconds, a new matrix is presented when it expires.

If you guess the character the remaining time is added to the score otherwise subtracted.

Sources are stored at:


Game was developed on a MSX2 emulator at

  1. connect to
  2. click on the first floppy icon below the blue screen
  3. Select "Add Disk Images"
  4. Choose "paz.dsk"
  5. type in:
load "a:paz.bas"


  1. connect to
  2. press ALT+B
  3. copy and paste source code
  4. type in:

WebMSX Launch URL:

MSXPen link:

Source Description

1 cls:?tab(17)"PAZ":DIMS$(16):R=RND(-TIME):KEYOFF:ONINTERVAL=50GOSUB10:goto9
  • initialize Random Number Generator
  • initialize E (timer) to zero
  • start the timer callback subroutine
2 CLS:?"PTS"P:R=RND(1):L=25*R:IFR>(1-R)THENM=0:N=L-1:ELSEM=L+1:N=25
  • clear screen
  • print points
  • generate the letter index to guess: L
  • select the wider intervall between: 0-L and L-25
3 FORI=0TO15:R=RND(1):S$(I)=CHR$(97+R*(N-M)+M):NEXTI:A$=CHR$(97+L):T%=RND(1)*3+1
  • generate random matrix and store it into the array S$()
  • the random matrix doesn't contains the choosen character
  • A$ contains the character to guess
  • T% contains the number of times that character must appaer
4 K%=0:FORI=0TOT%-1:K%=K%+RND(1)*4+1:S$(K%)=A$:NEXT:C=0:FORI=0TO3:FORJ=0TO3
  • For T% times, at random position, A$ is is inserted into the matrix
5 LOCATE15+I*2,8+J*2:?S$(I*4+J):NEXTJ,I:LOCATE16,5:?T%"X":E=10:INTERVALON:
  • Hint is shown
  • Time E is resetted to 10 seconds.
  • event callback is turned on
6 ifP>HthenH=P:goto6:elseK$=INKEY$:ifE=0thenC=T%:goto9:ELSEifK$<"a"orK$>"z"then6
  • a char is read from the keyboard
  • if time is over level is restarted
  • checks if the character pressed is valid
7 INTERVALOFF:FORI=0TO3:FORJ=0TO3:LOCATE15+I*2,8+J*2:K=I*4+J:ifS$(K)<>K$then?" "
  • event interval callback is turned off to avoid interference with the print
  • compute the number of times that KR$ appaers into the matrix: it could be different from A$ but be a valid solution.
8 NEXTJ,i:FORI=0TO15:ifS$(I)=K$THENC=C+1:locate16,16:?C""K$:next:elsenext
  • show on the matrix the character selected
9 locate15,22:?"ANY KEY";:k$=input$(1):IFC=T%thenP=P+E:goto2:elseP=P-E:goto2
  • if character pressed is present T% times into the matrix points P% is incremented, else subtracted.
  • in any case level is repeated
10 IFE=0THENreturn:ELSE E=E-1:LOCATE15,0:?"HIGH"H:locate30,0:?E"SECS":RETURN
  • event callback: it decrease time and show it on the screen.
  • Shows high score
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