#!/usr/bin/perl -l

sub generate {
  $base = $_[0];
  $interval = $_[1];
}                                      # create incrementor configurator

sub incrementor {
  $base += $interval;
}                                      # create incrementor

generate( 5, 2 );                      # configure first incrementor
print incrementor();                   # output: 7
print incrementor();                   # output: 9

@first_inc = ( $base, $interval );     # save first incrementor's state

generate( 3, 1);                       # configure second incrementor
print incrementor();                   # output: 4
print incrementor();                   # output: 5

@second_inc = ( $base, $interval );    # save second incrementor's state

generate( @first_inc );                # reload first incrementor's state
print incrementor();                   # output: 11
print incrementor();                   # output: 13

@first_inc = ( $base, $interval );     # save first incrementor's state

generate( @second_inc );               # reload second incrementor's state
print incrementor();                   # output: 6
print incrementor();                   # output: 7

=cut

All Output:

7
9
4
5
11
13
6
7

=end