diff --git a/chameleonic.p8 b/chameleonic.p8
index 0d28ada..d91f9e5 100644
--- a/chameleonic.p8
+++ b/chameleonic.p8
@@ -438,6 +438,8 @@ function level:spawn_exit()
   if (self:_mget(x,y)!=18) return
   for nx=x-1,x+1 do
    for ny=y-1,y+1 do
+    -- next check: is at least one of
+    -- nx or ny out of range [0, 15]?
     if (nx | ny) & 0xFFF0 ~= 0 then
      self._wins[_mix(nx,ny)]=true
     end