$month[0][0] = "January";
$month[0][1] = "Jan";
$month[1] = ["February", "Feb"];
push @month, ["March", "Mar"];
push @{$month[3]}, "April";
push @{$month[3]}, "Apr";

##</code><code>##

0  ARRAY(0x20381390)
   0  'January'
   1  'Jan'
1  ARRAY(0x20381528)
   0  'February'
   1  'Feb'
2  ARRAY(0x203815d0)
   0  'March'
   1  'Mar'
3  ARRAY(0x204424d0)
   0  'April'
   1  'Apr'

##</code><code>##

print $month[3][1]; # prints "Apr"