Moving an element

I am trying to see an object moving on the screen. This WORKS:

#!/usr/bin/env osascript

on run
    tell application "OmniGraffle"
        set activeWindow    to the front window
        set activeDocument  to the document     of the activeWindow
        set activeCanvas    to the canvas       of the activeWindow
        set allGraphics     to every graphic    of the activeCanvas

        repeat with theGraphic in allGraphics
            if  (exists the user name of theGraphic) then
                set graphicName to the user name of theGraphic
                if graphicName is "disco" then
                    set i to 0
                    repeat while i < 100
                        set curOrig to the origin of theGraphic
                        set the second item of curOrig to (the second item of curOrig) + 1
                        set origin of theGraphic to curOrig
                        delay .05
                        set i to i + 1
                    end repeat
                end if
            end if
        end repeat
    end tell
end run