diff --git a/README.md b/README.md
index 51b9d4a..7742f9d 100644
--- a/README.md
+++ b/README.md
@@ -44,6 +44,59 @@ In addition DocLib supports image links for the ingame manual:
 See examples in `manual_EN.md`.
 
 
+### Construction Plans
+
+This is a feature, mainly used by the mod techage to show construction plans of
+multi-block machines. But it can be used for any other mod, too.
+
+![Plan](https://github.com/joe7575/doclib/blob/main/construction_plan.png)
+
+A construction plan is a map with up to 12 * 10 fields. 
+Each field can contain a node/item, text, or an image.
+The arrangement is defined via a Lua table.
+
+This is an example of a map with 12 * 10 fields from the demo code in `node.lua`:
+
+
+```lua
+
+local ITEM1 = {"item", "doclib_demo_img1.png"}
+local ITEM2 = {"item", "doclib_demo_img2.png", "Tooltip 1"}
+local ITEM3 = {"item", "doclib_demo_img3.png", "Tooltip 2"}
+local ITEM4 = {"item", "doclib_demo_img4.png", "Tooltip 3"}
+local ITEM5 = {"item", "doclib_book_inv.png",  "doclib:manual"}
+local ITEM6 = {"item", "doclib:manual",  "doclib:manual"}
+local IMG_1 = {"img", "doclib_book_inv.png", "2,2"}
+local TEXT1 = {"text", "Top view"}
+local TEXT2 = {"text", "Pointless Demo"}
+local TEXT3 = {"text", "End"}
+
+local plan1 = {
+	{TEXT2, false, false, false, false, false, false, false, false, false, false, ITEM4},
+	{false, false, false, TEXT1, false, false, false, false, IMG_1, false, false, false},
+	{false, false, false, false, false, false, false, false, false, false, false, false},
+	{false, false, false, false, ITEM1, false, false, false, false, false, false, false},
+	{false, false, false, ITEM4, ITEM5, ITEM2, false, false, false, false, false, false},
+	{false, false, false, false, ITEM3, false, false, false, false, false, false, false},
+	{false, false, false, false, ITEM6, false, false, false, false, false, false, false},
+	{false, false, false, false, false, false, false, false, false, false, false, false},
+	{false, false, false, false, false, false, false, false, false, false, false, false},
+	{TEXT3, false, false, false, false, false, false, false, false, false, false, ITEM4},
+}
+
+doclib.add_manual_plan("doclib", "EN", "demo1", plan1)
+```
+
+- Unused field elements are set to `false` 
+- For a text field a table like `{"text", "Pointless Demo"}` is used
+- For an item field a table like `{"item", "doclib_demo_img2.png", "Tooltip 1"}` is used.
+  The third value is a tooltip. It can be a string, a node name, or `nil` for no tooltip.
+- For an image field a table like `{"img", "doclib_book_inv.png", "2,2"}` is used.
+  The third value is the image size in fields (width x height).
+
+With `doclib.add_manual_plan` the plan is stored under the name "demo1".
+
+
 ### License
 
 Copyright (C) 2023 Joachim Stolberg
diff --git a/textures/book.xcf b/textures/book.xcf
index a7c0064..97643c6 100644
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