See all valid Perl code ("use strict" is in force, else the results are less interesting) consisting of 3 typical characters with optional whitespace:

use strict;
use Algorithm::Loops 'NestedLoops';

my @chars= map chr($_), ord(' ') .. ord('~');
my @spaces= ( "", "\n", shift @chars );
my $iter= NestedLoops(
    [
        ( \@chars, \@spaces ) x 2, \@chars,
    ],
    {
        OnlyWhen => sub { @_ % 2 },
    },
);
sub dump { 1; }
sub exit { 1; }
$SIG{__WARN__}= sub { 1; };
close STDIN;
my @code;
while(  @code= $iter->()  ) {
    my $code= join '', @code;
    if(  eval "$code; 1"  ) {
        print "($code)\n";
    }
}
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It is trivial to expand this to look at larger code strings... but the results are less interesting, again. :)