diff --git a/xo-alloc2/docs/AAllocator-reference.rst b/xo-alloc2/docs/AAllocator-reference.rst
index faa6f15a..4bb0150f 100644
--- a/xo-alloc2/docs/AAllocator-reference.rst
+++ b/xo-alloc2/docs/AAllocator-reference.rst
@@ -12,21 +12,44 @@ Context
 .. ditaa::
     :--scale: 0.99
 
-    +--------------------------------+
-    |      IAllocator_DArena         |
-    +--------------------------------+
-    |      IAllocator_Xfer           |
-    +--------------------------------+
-    |      IAllocator_ImplType       |
-    +--------------+-----------------+
-    |cBLU          |    DArena       |
-    |   AAllocator +-----------------+
-    |              | ArenaConfig     |
-    +--------------+-----------------+
+    +-------------------------------+--------------------------------------+
+    |                               |  IAllocator_DX1Collector             |
+    |                               |  IAllocIterator_DX1CollectorIterator |
+    | IAllocator_DArena             |                                      |
+    | IAllocIterator_DArenaIterator +--------------------------------------+
+    |                               |             DX1Collector             |
+    |                               |        DX1CollectorIterator          |
+    |                               |                                      |
+    +-------------------------------+---------+----------------------------+
+    |               DArena                    |                            |
+    |               DArenaIterator            |                            |
+    +-----------------------------------------+       CollectorConfig      |
+    |               ArenaConfig               |                            |
+    +-----------------------------------------+----------------------------+
+
+    +----------------------------------+-----------------------------------+
+    |            RAllocator            |           RAllocIterator          |
+    +----------------------------------+-----------------------------------+
+    |        IAllocator_DX1Collector   |     IAllocIterator_DX1Collector   |
+    |        IAllocator_DArena         |     IAllocIterator_DArena         |
+    +----------------------------------+-----------------------------------+
+    |        IAllocator_Xfer           |     IAllocIterator_Xfer           |
+    |        IAllocator_Any            |     IAllocIterator_Any            |
+    +----------------------------------+-----------------------------------+
+    |           AAllocator             |           AAllocIterator          |
+    +----------------------------------+-----------------------------------+
+
+    +---------------+------------------+----------------------+------------+
+    |               |                  |       AllocInfo      |            |
+    |  generation   |                  +----------------------+            |
+    |  object_age   |    AllocError    |   AllocHeaderConfig  |  cmpresult |
+    |     role      |                  +----------------------+            |
+    |               |                  |     AllocHeader      |            |
+    +---------------+------------------+----------------------+------------+
 
 .. code-block:: cpp
 
-    #incldue <xo/alloc2/AAllocator.hpp>
+    #include <xo/alloc2/AAllocator.hpp>
 
 Class
 -----
diff --git a/xo-alloc2/docs/DArena-reference.rst b/xo-alloc2/docs/DArena-reference.rst
index 8ea46f98..8222f929 100644
--- a/xo-alloc2/docs/DArena-reference.rst
+++ b/xo-alloc2/docs/DArena-reference.rst
@@ -28,21 +28,44 @@ Context
     #include <xo/alloc2/DArena.hpp>
 
 
-Arena memory layout::
+Arena memory layout
+.. code-block:: text
 
-    <----------------------------size-------------------------->
-    <------------committed-----------><-------uncommitted------>
-    <--allocated-->
+      <----------------------------size-------------------------->
+      <------------committed-----------><-------uncommitted------>
+      <--allocated-->
 
-    XXXXXXXXXXXXXXX___________________..........................
-   ^               ^                  ^                         ^
-   lo              free               limit                     hi
+      XXXXXXXXXXXXXXX___________________..........................
+     ^               ^                  ^                         ^
+     lo              free               limit                     hi
 
-    [X] allocated:   in use
-    [_] committed:   physical memory obtained
-    [.] uncommitted: mapped in virtual memory, not backed by memory
+      [X] allocated:   in use
+      [_] committed:   physical memory obtained
+      [.] uncommitted: mapped in virtual memory, not backed by memory
 
 
+Allocation layout
+.. code-block:: text
+
+                     free_(pre)
+                         v
+
+                         <-------------z1--------------->
+                < guard ><  hz  ><     req_z     >< dz  >< guard >
+
+      used <==  +++++++++0000zzzz@@@@@@@@@@@@@@@@@ppppppp+++++++++ ==> avail
+
+                         ^       ^                                ^
+                         header  mem                              |
+                         ^                                        |
+                         last_header_                   free_(post)
+
+                 [+] guard after each allocation, for simple sanitize checks
+                 [0] unused header bits (avail to application)
+                 [z] record allocation size
+                 [@] new allocated memory
+                 [p] padding (to uintptr_t alignment)
+
 Class
 -----
 
diff --git a/xo-alloc2/include/xo/alloc2/Collector.hpp b/xo-alloc2/include/xo/alloc2/Collector.hpp
index f3523552..45c7fdb5 100644
--- a/xo-alloc2/include/xo/alloc2/Collector.hpp
+++ b/xo-alloc2/include/xo/alloc2/Collector.hpp
@@ -1,5 +1,5 @@
 /** @file Collector.hpp
-*
+ *
  *  @author Roland Conybeare, Dec 2025
  **/
 
diff --git a/xo-alloc2/include/xo/alloc2/arena/ArenaConfig.hpp b/xo-alloc2/include/xo/alloc2/arena/ArenaConfig.hpp
index dcac455a..93fc35b8 100644
--- a/xo-alloc2/include/xo/alloc2/arena/ArenaConfig.hpp
+++ b/xo-alloc2/include/xo/alloc2/arena/ArenaConfig.hpp
@@ -6,7 +6,7 @@
 #pragma once
 
 #include "alloc/AllocHeaderConfig.hpp"
-#include "alloc/AllocError.hpp"
+//#include "alloc/AllocError.hpp"
 #include <string>
 #include <cstdint>
 
diff --git a/xo-alloc2/include/xo/alloc2/arena/DArena.hpp b/xo-alloc2/include/xo/alloc2/arena/DArena.hpp
index 36e87c4d..e44b6512 100644
--- a/xo-alloc2/include/xo/alloc2/arena/DArena.hpp
+++ b/xo-alloc2/include/xo/alloc2/arena/DArena.hpp
@@ -6,6 +6,7 @@
 #pragma once
 
 #include "ArenaConfig.hpp"
+#include "alloc/AllocError.hpp"
 #include "alloc/AllocInfo.hpp"
 
 namespace xo {