Step 2: Add a namespace eval block at top of script, put all
 variable names in this block to provide documentation.

Final code:

namespace eval ::sud {

    variable rows
    variable cols
    variable squares

    variable arabicmode
    variable duplicatesfound
    variable invalidfound
    variable kanji1to9

    variable cellbgcolorA 
    variable cellbgcolorB
    variable cellerrorcolor
    variable celldupcolor 
    variable cellchangedcolor
    variable checkcolor

    variable arabicarray
    variable cellarray
    variable cellbgcolorarray
    variable kanjiarray 
    variable possarray
}