54 wasteful bytes; looks kinda neat though. interactive. (c64)

flower tower

;
; wallpaper scroll / flower tower (interactive)
;
        * = 4096
        
        lda #6
        sta $d020        
start   ;
        ; user input to init field color and width
        ;
        lda $c5 
        lsr
        tay
        sta $286
        ;..
loop
        dey
        ;..
        lda $2 ; use the first free zp adress as and-3 buffer
        adc #1
        and #3
        sta $2
        ;
        lda #107 ; chr$(107) as offset looks quite nice
        adc $2
        ;..
        jsr $ffd2
        ;..
        sta $d418 ; audio
        ;..
        cpy #0
        bne loop
        ;
        ; border pieces per line, in their own color
        ;
        lda #14        
        sta $286
        lda #103
        jsr $ffd2
        lda #13
        jsr $ffd2
        ;
        lda #104
        jsr $ffd2
        ;
        bcc start