diff --git a/f/trac.c b/f/trac.c
index 32cdb6e8d4..56ac2845a1 100644
--- a/f/trac.c
+++ b/f/trac.c
@@ -487,7 +487,7 @@ u2_tx_in_profile(u2_ray wir_r)
 
   return u2_trac_at(rac_r, cor.pro);
 }
-
+ 
 static u2_bean
 _tx_map_ok(u2_wire wir_r,
            u2_noun a)
diff --git a/include/f/liar.h b/include/f/meme.h
similarity index 98%
rename from include/f/liar.h
rename to include/f/meme.h
index 06f8bf3344..4c2ef9699a 100644
--- a/include/f/liar.h
+++ b/include/f/meme.h
@@ -1,4 +1,4 @@
-/* include/rail.h
+/* include/meme.h
 **
 ** This file is in the public domain.
 */
@@ -12,6 +12,19 @@
 #     define  u2_leak_off  (COD_w = 0)
 #   endif
 
+  /** Data structures.
+  **/
+    typedef struct _u2_road {
+      void* cap_v;   // top of transient region
+      void* hat_v;   // top of new durable region
+      void* mat_v;   // bottom of transient region
+      void* rut_v;   // bottom of new durable region
+    } u2_road;
+
+    typedef struct _u2_town {
+      u2_town* par_u;
+    } u2_town;
+
   /** Data types.
   **/
     /** Ray types.