Upon more reflection, it sounds like your app is like a spreadsheet. So I offer some code to get you started if you want to go that way. This is a bit different than packing your own widgets although you can do that!

The TableMatrix data structure is weird in that coordinates are "$row,$column" as a single hash key. Anyway here is some runnable code for you to play with...of course the details can get very complex! Like when you click on a square with left,right,middle mouse context and want pop-up menus and such.

Unless this critter has to be interactive with the user, I would suggest making a .CSV file or .XLS Excel file and using that for the display. Anyway here is a simple framework to make a Tk spreadsheet:

#!/usr/bin/perl -w
use strict;

use Tk;
use Tk::TableMatrix::Spreadsheet;
  
my %hash;

my $mw = MainWindow -> new;
$mw -> title ("Just Some Demo");
  
$mw ->Button(-text => "Quit!",
         -command => sub {exit} ) ->pack;
  
my $top = $mw->Scrolled('Spreadsheet', 
                              -rows          => 21, 
                              -cols          => 11,
                              -width         => 6, 
                              -height        => 12,
                              -titlerows     => 1, 
                              -titlecols     => 0,
                              -variable      => \%hash,
                              -selectmode    => 'single', 
                              -resizeborders => 'both',
                              -bg            => 'white',
                          )->pack(-expand =>1, -fill=>'both');
$hash{"0,1"}="xyzzy";
$hash{"2,3"}="coord:2,3";
                          
MainLoop;
[download]

Tk is cool and lot's can be done with it.