proc sudoku2 {grid} {
    #check rows
    foreach row $grid {
        if {[checkRow [removeDummy $row]] == 0} {
            return false
        }
    }

    #check Column
    foreach row [getRows $grid] {
        if {[checkRow [removeDummy $row]] == 0} {
            return false
        }
    }

    #Check square
    foreach row [getSquares $grid] {
        if {[checkRow [removeDummy $row]] == 0} {
            return false
        }
    }

    return true
}

proc checkRow {row} {
    if {[llength $row] == 0} {
        return 1
    }
    return [string equal [lsort -unique $row] [lsort $row]]
}

proc removeDummy {values} {
    return [lsearch -inline -all -not $values  "." ]
}

proc getSquares {a} {
    array set tempArray {}

    for {set i 0} {$i<9} {set i [expr $i +3]} {
        for {set j 0} {$j<9} {set j [expr $j +3]} {
            set square ""
            for {set k 0} {$k<3} {incr k} {
                set row [lindex $a [expr $k+$i]]
                for {set l 0} {$l<3} {incr l} {
                    lappend square [lindex [split $row " "] [expr $l + $j]]
                }
            }
            set tempArray([expr ($i/3)+($j)]) $square
        }
    }
    for {set i 0} {$i < 9} {incr i} {
        lappend retVal $tempArray($i)
    }
    return $retVal
}

proc getRows {a} {
    array set tempArray {}
    set retVal ""
    foreach row $a {
        for {set i 0} {$i < 9} {incr i} {
            lappend tempArray($i) [list [lindex $row $i]]
        }
    }
    for {set i 0} {$i < 9} {incr i} {
            lappend retVal $tempArray($i)
    }
    return $retVal
}