my $N = 4;
my $depth = 3;
my $i2 = nested_for([   [ 0..$N ],
             ( sub { [$_+1..$N] } ) x ($depth-1),
         ]);
print "@args\n" while @args = $i2->();

##</code><code>##

0 1 2
0 1 3
0 1 4
0 2 3
0 2 4
0 3 4
0 4
1 2 3
1 2 4
1 3 4
1 4
2 3 4
2 4
3 4
4