A natural way to do this seems to me to think of it as the number of ways of placing the ones in a string of size $ones + $zeros : 
use Algorithm::ChooseSubsets;
use strict;

my $ones = 2;
my $twos = 3;

my $i = Algorithm::ChooseSubsets->new($ones + $twos,$ones);
while (my $x = $i->next) {
    my %on = map {($_ => 1)} @$x;
    my @str = map { $on{$_} ? '1' : '0' } (0..$ones+$twos-1);
    print @str,"\n";
}

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In reply to Re: One Zero variants_without_repetition by bduggan
in thread One Zero variants_without_repetition by thenetfreaker

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