diff --git a/2016/18/1.pl b/2016/18/1.pl
new file mode 100644
index 0000000..976673f
--- /dev/null
+++ b/2016/18/1.pl
@@ -0,0 +1,34 @@
+use 5.20.0;
+
+use experimental qw/ postderef /;
+
+my @levels = (
+    map { chomp; [ 
+        map { $_ eq '^' } split '' ] } <>
+);
+
+use DDP;
+
+p @levels;
+my $sum = 0;
+use List::AllUtils qw/ sum /;
+
+for ( 1..400000-1 ) {
+    my @previous = ( 0, $levels[-1]->@* );
+    my @new;
+    while( @previous >= 2 ) {
+        my( $left, $mid, $right ) = @previous;
+        push @new, 
+            ( $left && $mid && ! $right )
+         || ( !$left && $mid && $right )
+         || ( $left && !$mid && !$right )
+         || ( !$left && !$mid && $right );
+         shift @previous;
+    }
+    push @levels, \@new;
+
+    $sum += sum map { !$_ } map { @$_ } shift @levels;
+}
+
+
+say sum $sum, map { !$_ } map { @$_ } @levels;
diff --git a/2016/18/input.txt b/2016/18/input.txt
new file mode 100644
index 0000000..d0f699e
--- /dev/null
+++ b/2016/18/input.txt
@@ -0,0 +1 @@
+^^.^..^.....^..^..^^...^^.^....^^^.^.^^....^.^^^...^^^^.^^^^.^..^^^^.^^.^.^.^.^.^^...^^..^^^..^.^^^^