From c0092bd5465ac448e7898342f1e25efc26737a2a Mon Sep 17 00:00:00 2001
From: "Joseph C. Sible" <josephcsible@users.noreply.github.com>
Date: Mon, 17 Nov 2025 00:00:22 -0500
Subject: [PATCH] Fix Free Fall crashing in horodisk land structure

It still doesn't work completely right (in particular, you'll get the
"warning: a looped line" message, and gravity will point the wrong way on
some of the outermost tiles), but this is way better than the whole game
crashing whenever you get near the land at all.
---
 complex2.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/complex2.cpp b/complex2.cpp
index 697cd48b..08da1681 100644
--- a/complex2.cpp
+++ b/complex2.cpp
@@ -224,7 +224,7 @@ EX namespace westwall {
   void build(vector<cell*>& whirlline, int d) {
     again: 
     cell *at = whirlline[isize(whirlline)-1];
-    cell *prev = whirlline[isize(whirlline)-2];
+    cell *prev = isize(whirlline) >= 2 ? whirlline[isize(whirlline)-2] : NULL;
     if(looped(whirlline)) return;
     for(int i=0; i<at->type; i++) 
       if(at->move(i) && coastvalEdge1(at->move(i)) == d && at->move(i) != prev) {