use strict;
use warnings;

doShift (2, 5);
print "\n";
doShift (3, 6);
print "\n";


sub doShift {
    my ($ones, $bits, $pattern, $limit) = @_;
    
    --$ones;
    $limit ||= $bits;
    $pattern ||= 0;
    
    for my $right ($ones .. $limit - 1) {
        if ($ones) {
            doShift ($ones, $bits, $pattern | (1 << $right), $right);
        } else {
            printf "%0*b\n", $bits, $pattern | (1 << $right);
        }
    }
}

##</code><code>##

00011
00101
00110
01001
01010
01100
10001
10010
10100
11000

000111
001011
001101
001110
010011
010101
010110
011001
011010
011100
100011
100101
100110
101001
101010
101100
110001
110010
110100
111000