txt$ = "Hello World! "
    txtLength = len(txt$)
    direction=1

    NoMainWin

    open "Rosetta Task: Animation" for graphics_nsb as #demo
    #demo "Trapclose [quit]"
    #demo "down"
    #demo "Font Verdana 20 Bold"
    #demo "When leftButtonUp [changedirection]"

    timer 150 , [draw]
    wait

[draw]
    if direction then
        txt$ = right$(txt$, 1);left$(txt$, txtLength - 1)
    else
        txt$ = right$(txt$, txtLength - 1);left$(txt$, 1)
    end if
    #demo "discard"
    #demo "place 50 100"
    #demo "\";txt$
    wait

[changedirection]
    direction = not(direction)
    wait

[quit]
    timer 0
    close #demo
    end