Tmp

div.code { counter-reset: linenumber; }
div.code p {
counter-increment: linenumber;
margin: 0;
}
div.code p::before {
content: counter(linenumber);
width: 2.25em;
display: inline-block;
text-align: right;
border-right: 1px dashed #DDD;
padding-right: 3px;
margin-right: 6px;
-webkit-user-select: none; / Chrome/Safari /
-moz-user-select: none; / Firefox /
-ms-user-select: none; / IE 10+ /
user-select: none; / Likely future /
}
[[/module]]

CSS

div.code {  counter-reset: linenumber; }
div.code p {
    counter-increment: linenumber;
    margin: 0;
}
div.code p::before {
    content: counter(linenumber);
    width: 2.25em;
    display: inline-block;
    text-align: right;
    border-right: 1px dashed #DDD;
    padding-right: 3px;
    margin-right: 6px;
    -webkit-user-select: none;  /* Chrome/Safari */
    -moz-user-select: none;     /* Firefox */
    -ms-user-select: none;      /* IE 10+ */
    user-select: none;          /* Likely future */ 
}

Correct Format

:Full

:FnOff

:AxesOff

:0→Xmin:1→ΔX

:0→Ymin:1→ΔY

:ClrDraw

:Vertical Xmin

:Vertical Xmax

:Horizontal Ymin

:Horizontal Ymax

:60→A:92→B

:2→C:2→D:25→G

:Pxl-On(A,B

:Pxl-On(C,D

:Text(-1,28,31,"READY?

:Pause

:For(E,26,36

:Line(29,E,67,E,0

:End

:Repeat G=45 or not(pxl-Test(A,B) and pxl-Test(C,D

:getKey

:If Ans

:Ans→G

:A+(G=34)-(G=25→A

:B+(G=26)-(G=24→B

:1+pxl-Test(C+1,D

:Ans+(Ans=2 and pxl-Test(C,D-1

:Ans+(Ans=3 and pxl-Test(C-1,D→F

:C+(Ans=1)-(Ans=3→C

:D+(F=4)-(F=2→D

:Pxl-Change(A,B

:Pxl-Change(C,D

:End

Incorrect Format

:Full
:FnOff
:AxesOff
:0→Xmin:1→ΔX
:0→Ymin:1→ΔY
:ClrDraw
:Vertical Xmin
:Vertical Xmax
:Horizontal Ymin
:Horizontal Ymax
:60→A:92→B
:2→C:2→D:25→G
:Pxl-On(A,B
:Pxl-On(C,D
:Text(-1,28,31,"READY?
:Pause
:For(E,26,36
:Line(29,E,67,E,0
:End
:Repeat G=45 or not(pxl-Test(A,B) and pxl-Test(C,D
:getKey
:If Ans
:Ans→G
:A+(G=34)-(G=25→A
:B+(G=26)-(G=24→B
:1+pxl-Test(C+1,D
:Ans+(Ans=2 and pxl-Test(C,D-1
:Ans+(Ans=3 and pxl-Test(C-1,D→F
:C+(Ans=1)-(Ans=3→C
:D+(F=4)-(F=2→D
:Pxl-Change(A,B
:Pxl-Change(C,D
:End

Code Block

:Full
:FnOff
:AxesOff
:0→Xmin:1→ΔX
:0→Ymin:1→ΔY
:ClrDraw
:Vertical Xmin
:Vertical Xmax
:Horizontal Ymin
:Horizontal Ymax
:60→A:92→B
:2→C:2→D:25→G
:Pxl-On(A,B
:Pxl-On(C,D
:Text(-1,28,31,"READY?
:Pause
:For(E,26,36
:Line(29,E,67,E,0
:End
:Repeat G=45 or not(pxl-Test(A,B) and pxl-Test(C,D
:getKey
:If Ans
:Ans→G
:A+(G=34)-(G=25→A
:B+(G=26)-(G=24→B
:1+pxl-Test(C+1,D
:Ans+(Ans=2 and pxl-Test(C,D-1
:Ans+(Ans=3 and pxl-Test(C-1,D→F
:C+(Ans=1)-(Ans=3→C
:D+(F=4)-(F=2→D
:Pxl-Change(A,B
:Pxl-Change(C,D
:End

Authors: KG