Michael Doornbos (of https://imapenguin.com/) posted two “10 PRINT” articles for our beloved small 6502 SBC’s.

The KIM-1 version displays on the seven segment LED displays. The AIM 65 prints it on the thermal printer.

KIM-1 version of 10 PRINT in BASIC and assember

10 PRINT CHR$(47+INT(RND(0)*2)*45);:GOTO 10

; BY MICHAEL DOORNBOS MIKE@IMAPENGUIN.COM; 2025 
; SOFT START AT $0200

; THIS PROGRAM GENERATES A RANDOM PATTERN OF SLASHES AND BACKSLASHES
; AND DISPLAYS IT ON THE KIM-1'S 7-SEGMENT DISPLAY.

; THE PATTERN SCROLLS TO THE LEFT, CREATING A CONTINUOUS EFFECT.

; A LOT OF THIS CODE IS BORROWED FROM:
; https://netzherpes.de/blog/index.php?entry=KIM-1-scrolltext
; kim_msg.asm
; testing lin2c64 6510 assembler
; using J. Butterfield's scan display from Wumpus
; 01/03/2013 ces



; CONSTANTS FOR 7-SEGMENT DISPLAY CHARACTERS
BACKSLASH  .EQU $64        ; BACKSLASH CHARACTER
SLASH      .EQU $52        ; FORWARD SLASH CHARACTER
SPC        .EQU $80        ; SPACE CHARACTER

; KIM-1 HARDWARE ADDRESSES
SAD     .EQU $1740      ; DATA PORT FOR PINS 1-4
SADD    .EQU $1741      ; DATA DIRECTION REGISTER A
SBD     .EQU $1742      ; DATA PORT FOR PINS 5-6
SBDD    .EQU $1743      ; DATA DIRECTION REGISTER B
TIMER2  .EQU $1747      ; OPTIONAL 2ND 6532 TIMER
LOUT    .EQU $7F        ; SET PINS AS OUTPUT TO LEFT 4 LEDS
ROUT    .EQU $1E        ; SET PINS AS OUTPUT TO RIGHT 2 LEDS

; ZERO PAGE VARIABLES
SEED    .EQU $00D0      ; RANDOM SEED LOCATION
TMR     .EQU $00DB      ; TIMER COUNTER
PTR     .EQU $00DC      ; POINTER
XFRHI   .EQU $00DD      ; USED FOR CHARACTER BUFFER HIGH BYTE
XFRLO   .EQU $00DE      ; USED FOR CHARACTER BUFFER LOW BYTE
TMP1    .EQU $00DF      ; TEMPORARY STORAGE
CBUFF   .EQU $00E8      ; CHARACTER BUFFER (6 BYTES)
MSGBUF  .EQU $0180      ; BUFFER FOR GENERATED PATTERNS (30 BYTES)

        .ORG $0200      ; START OF PROGRAM CODE

MAIN    
        ; CLEAR THE MESSAGE BUFFER FIRST TO PREVENT GLITCHES
        LDX #$00
CLRLOOP LDA #SPC        ; USE SPACE CHARACTER TO INITIALIZE
        STA MSGBUF,X
        INX
        CPX #$30        ; CLEAR THE ENTIRE BUFFER AREA
        BNE CLRLOOP
        
        LDA #$00        ; ADD NULL TERMINATOR AT THE END
        STA MSGBUF+23
        
        ; INITIALIZE THE TIMER
        LDA #$FF        ; LOAD MAXIMUM VALUE
        STA TIMER2      ; START TIMER
        
        ; USE TIMER VALUE AS SEED
        LDA TIMER2      ; READ CURRENT TIMER VALUE
        STA SEED        ; USE AS RANDOM SEED
        BNE SEEDOK      ; IF NOT ZERO, IT'S FINE
        INC SEED        ; OTHERWISE INCREMENT TO MAKE NON-ZERO
        
SEEDOK  JSR GENPAT      ; GENERATE INITIAL PATTERN
        
INFINIT LDY #>MSGBUF    ; LOAD BUFFER LOCATION
        LDA #<MSGBUF
        JSR SCAN        ; DISPLAY THE PATTERN
        
        ; GENERATE NEW RANDOM SLASH AT END OF BUFFER
        JSR RANDOM      ; GET RANDOM BIT
        BCC GENBACK     ; BRANCH IF CARRY CLEAR (50% CHANCE)
        
        LDA #SLASH      ; FORWARD SLASH
        JMP STORE
        
GENBACK LDA #BACKSLASH  ; BACKSLASH
        
STORE   STA MSGBUF+22   ; ADD NEW CHARACTER TO END OF BUFFER
        
        ; SHIFT BUFFER LEFT ONE POSITION (SCROLL EFFECT)
        LDX #$00        ; START AT FIRST POSITION
SHIFT   LDA MSGBUF+1,X  ; GET NEXT CHARACTER
        STA MSGBUF,X    ; STORE IN CURRENT POSITION
        INX             ; MOVE TO NEXT POSITION
        CPX #$22        ; CHECK IF WE&#39;RE AT END OF BUFFER
        BNE SHIFT       ; CONTINUE IF NOT AT END
        
        ; ENSURE NULL TERMINATOR IS ALWAYS PRESENT
        LDA #$00
        STA MSGBUF+23
        
        JMP INFINIT     ; LOOP FOREVER

; GENERATE INITIAL PATTERN BUFFER WITH RANDOM SLASHES
GENPAT  LDX #$00        ; START AT FIRST POSITION
GPLOOP  JSR RANDOM      ; GET RANDOM BIT
        BCC GBACK       ; BRANCH IF CARRY CLEAR
        
        LDA #SLASH      ; FORWARD SLASH
        JMP GSTORE
        
GBACK   LDA #BACKSLASH  ; BACKSLASH
        
GSTORE  STA MSGBUF,X    ; STORE IN BUFFER
        INX             ; NEXT POSITION
        CPX #$17        ; CHECK IF BUFFER IS FULL
        BNE GPLOOP      ; CONTINUE IF NOT FULL
        
        LDA #$00        ; ADD NULL TERMINATOR
        STA MSGBUF+23   ; AT END OF BUFFER
        RTS             ; RETURN

; RANDOM NUMBER GENERATOR (8-BIT LFSR)
RANDOM  LDA SEED        ; LOAD CURRENT SEED
        ASL             ; SHIFT LEFT (C GETS HIGH BIT)
        BCC NOEOR       ; SKIP EOR IF BIT 7 WAS 0
        EOR #$B4        ; APPLY FEEDBACK POLYNOMIAL
NOEOR   STA SEED        ; STORE UPDATED SEED
        RTS             ; RETURN WITH CARRY = RANDOM BIT

; SCANNING ROUTINE FROM ORIGINAL CODE
SCAN    STY XFRLO       ; Y AND A GET LOADED BEFORE JSR TO SCAN
        STA XFRHI
        LDA #$07        ; INIT SCAN FORWARD
        STA TMP1
        LDY #$05        ; INIT Y
CONT    LDX #$05        ; INIT X
CHAR    LDA (XFRHI),Y   ; GET CHARACTER
        CMP #$00        ; LAST CHARACTER?
        BNE MORE        ; IF NOT, CONTINUE
        RTS
MORE    STA CBUFF,X     ; STORE CHAR
        DEY             ; SET UP NEXT CHAR
        DEX             ; SET UP NEXT STORE LOC
        BPL CHAR        ; LOOP IF NOT 6TH CHAR
        CLD             ; BINARY MODE
        CLC             ; PREPARE TO ADD (CLEAR CARRY FLAG)
        TYA             ; GET CHAR POINTER
        ADC TMP1        ; UPDATE FOR 6 NEW CHARACTERS
        STA PTR         ; SAVE NEW POINTER
        JSR DSPDLY      ; DELAY DISPLAY
        LDY PTR         ; RESTORE POINTER
        JMP CONT        ; CONTINUE WITH REST OF MESSAGE

DSPDLY  LDX #$0A        ; SET THE DELAY RATE HERE
        STX TMR         ; PUT IN DECR. LOCATION
TIME    LDA #$52        ; LOAD TIMER
        STA TIMER2      ; START TIMER
LITE    JSR DISP        ; GOSUB DISPLAY RTN
        BIT TIMER2      ; TIMER DONE?
        BPL LITE        ; IF NOT, LOOP
        DEC TMR         ; DECREMENT TIMER COUNTER
        BNE TIME        ; NOT FINISHED
        RTS             ; NOW GET 6 NEW CHARACTERS

DISP    LDA #LOUT       ; CHANGE LEFT LED SEGMENTS
        STA SADD        ; TO OUTPUTS
        LDY #$00        ; INIT RECALL INDEX
        LDX #$09        ; INIT DIGIT NUMBER
SIX     LDA CBUFF,Y     ; GET CHARACTER
        STY $00FC       ; SAVE Y FOR MONITOR DISP ROUTINE
        JSR $1F4E       ; MONITOR ROUTINE - DISP CHAR, DELAY 500 CYCLES
        INY             ; SET UP FOR NEXT CHAR
        CPY #$06        ; 6 CHAR DISPLAYED?
        BCC SIX         ; NO
        RTS

AIM 65 version in BASIC

10 PRINTCHR$(47+(INT(RND(1)*2)*45));:GOTO 10

that print random ‘/’ or ‘\’