use strict;
use warnings;
use Tk;

my $mw = MainWindow->new();

my $buttonID = 1;

for my $x (0 .. 2) {
    for my $y (0 .. 2) {
        $mw->Button(-text => $buttonID)->grid(-row => $x, -column => $y);
        $buttonID++;
    }
}

MainLoop();