#!/usr/bin/perl -w

use Data::Dumper;

$a1 = 1;
$a2 = 2;
$a3 = 3;
$b1 = 4;
$b2 = 5;
$b3 = 6;
$c1 = 7;
$c2 = 8;
$c3 = 9;
%squares = (a1 => $a1, a2 => $a2, a3 => $a3, b1 => $b1, b2 => $b2, b3 => $b3, c1 => $c1, c2 => $c2, c3 => $c3);
print "Remove which one? ";
chomp ($response = <STDIN>);
&make_blank();
print Dumper %squares;
print "\n";
print %squares;

# makes the moved piece blank
sub make_blank() {
  foreach $key (keys %squares) {
    ($squares{$key} = "") if ($key eq $response);
  }
}