diff --git a/vector-space.md b/vector-space.md
index 51e80dd..79b32f1 100644
--- a/vector-space.md
+++ b/vector-space.md
@@ -38,10 +38,10 @@ It's probable that in version zero we won't implement garbage collection of vect
 
 So the header now looks like this:
 
-    +-----+--------------+------+------+---------------+
-    | 0   | 32           | 96   | 160  | 168  ...size /
-    | tag | vecp-pointer | size | mark | payload...  /
-    +-----+--------------+------+------+------------+
+    +-----+--------------+------+------+------------------------+
+    | 0   | 32           | 96   | 160  | 168  ...(167 + size) /
+    | tag | vecp-pointer | size | mark | payload...           /
+    +-----+--------------+------+------+--------------------+
 
 #### Alternative mark-bit strategy