diff --git a/plantuml/gilded-rose.png b/plantuml/gilded-rose.png
new file mode 100644
index 00000000..3f79be92
Binary files /dev/null and b/plantuml/gilded-rose.png differ
diff --git a/plantuml/gilded-rose.puml b/plantuml/gilded-rose.puml
new file mode 100644
index 00000000..1d36cb1d
--- /dev/null
+++ b/plantuml/gilded-rose.puml
@@ -0,0 +1,72 @@
+@startuml
+
+skinparam backgroundColor transparent
+
+start
+note left
+    Do this for each item in the list.
+    An item has a name, a sell in value and a quality value
+end note
+
+if (not "Aged Brie" and not "Backstage passes to a TAFKAL80ETC concert") then (yes)
+    if (quality > 0) then (yes)
+        if (not "Sulfuras, Hand of Ragnaros") then (yes)
+            :lower quality with 1;
+        else (no)
+        endif
+    else (no)
+    endif
+else (no)
+    if (quality < 50) then (yes)
+        :increase quality with 1;
+        if ("Backstage passes to a TAFKAL80ETC concert") then (yes)
+            if (sell in < 11) then (yes)
+                if (quality < 50) then (yes)
+                    :increase quality with 1;
+                else (no)
+                endif
+            else (no)
+            endif
+            if (sell in < 6) then (yes)
+                if (quality < 50) then (yes)
+                    :increase quality with 1;
+                else (no)
+                endif
+            else (no)
+            endif
+        else (no)
+        endif
+    else (no)
+    endif
+endif
+
+if (not "Sulfuras, Hand of Ragnaros") then (yes)
+    :lower sell in with 1;
+else (no)
+endif
+
+if (sell in < 0) then (yes)
+    if (not "Aged Brie") then (yes)
+        if (not "Backstage passes to a TAFKAL80ETC concert") then (yes)
+            if (quality > 0) then (yes)
+                if (not "Sulfuras, Hand of Ragnaros") then (yes)
+                    :lower quality with 1;
+                else (no)
+                endif
+            else (no)
+            endif
+        else (no)
+            :lower quality with quality;
+        endif
+    else (no)
+        if (quality < 50) then (yes)
+            :increase quality with 1;
+        else (no)
+        endif
+    endif
+else (no)
+endif
+
+stop
+
+@enduml
diff --git a/plantuml/history/01_lower-both-values.puml b/plantuml/history/01_lower-both-values.puml
new file mode 100644
index 00000000..8fa637bc
--- /dev/null
+++ b/plantuml/history/01_lower-both-values.puml
@@ -0,0 +1,12 @@
+@startuml
+
+skinparam backgroundColor transparent
+
+start
+
+:lower quality with 1;
+:lower sell in with 1;
+
+stop
+
+@enduml
diff --git a/plantuml/history/02_sell-by-passed.puml b/plantuml/history/02_sell-by-passed.puml
new file mode 100644
index 00000000..3b2c317d
--- /dev/null
+++ b/plantuml/history/02_sell-by-passed.puml
@@ -0,0 +1,17 @@
+@startuml
+
+skinparam backgroundColor transparent
+
+start
+
+:lower quality with 1;
+:lower sell in with 1;
+
+if (sell in < 0) then (yes)
+    :lower quality with 1;
+else (no)
+endif
+
+stop
+
+@enduml
diff --git a/plantuml/history/03_quality-never-negative.puml b/plantuml/history/03_quality-never-negative.puml
new file mode 100644
index 00000000..b2b9ed7e
--- /dev/null
+++ b/plantuml/history/03_quality-never-negative.puml
@@ -0,0 +1,24 @@
+@startuml
+
+skinparam backgroundColor transparent
+
+start
+
+if (quality > 0) then (yes)
+    :lower quality with 1;
+else (no)
+endif
+
+:lower sell in with 1;
+
+if (sell in < 0) then (yes)
+    if (quality > 0) then (yes)
+        :lower quality with 1;
+    else (no)
+    endif
+else (no)
+endif
+
+stop
+
+@enduml
diff --git a/plantuml/history/04_aged-brie.puml b/plantuml/history/04_aged-brie.puml
new file mode 100644
index 00000000..7b74e874
--- /dev/null
+++ b/plantuml/history/04_aged-brie.puml
@@ -0,0 +1,32 @@
+@startuml
+
+skinparam backgroundColor transparent
+
+start
+
+if (not "Aged Brie") then (yes)
+    if (quality > 0) then (yes)
+        :lower quality with 1;
+    else (no)
+    endif
+else (no)
+    :increase quality with 1;
+endif
+
+:lower sell in with 1;
+
+if (sell in < 0) then (yes)
+    if (not "Aged Brie") then (yes)
+        if (quality > 0) then (yes)
+            :lower quality with 1;
+    else (no)
+        endif
+    else (no)
+        :increase quality with 1;
+    endif
+else (no)
+endif
+
+stop
+
+@enduml
diff --git a/plantuml/history/05_quality-max-50.puml b/plantuml/history/05_quality-max-50.puml
new file mode 100644
index 00000000..69cc86d0
--- /dev/null
+++ b/plantuml/history/05_quality-max-50.puml
@@ -0,0 +1,38 @@
+@startuml
+
+skinparam backgroundColor transparent
+
+start
+
+if (not "Aged Brie") then (yes)
+    if (quality > 0) then (yes)
+        :lower quality with 1;
+    else (no)
+    endif
+else (no)
+    if (quality < 50) then (yes)
+        :increase quality with 1;
+    else (no)
+    endif
+endif
+
+:lower sell in with 1;
+
+if (sell in < 0) then (yes)
+    if (not "Aged Brie") then (yes)
+        if (quality > 0) then (yes)
+            :lower quality with 1;
+        else (no)
+        endif
+    else (no)
+        if (quality < 50) then (yes)
+            :increase quality with 1;
+        else (no)
+        endif
+    endif
+    else (no)
+endif
+
+stop
+
+@enduml
diff --git a/plantuml/history/06_sulfuras.puml b/plantuml/history/06_sulfuras.puml
new file mode 100644
index 00000000..25350c1d
--- /dev/null
+++ b/plantuml/history/06_sulfuras.puml
@@ -0,0 +1,47 @@
+@startuml
+
+skinparam backgroundColor transparent
+
+start
+
+if (not "Aged Brie") then (yes)
+    if (quality > 0) then (yes)
+        if (not "Sulfuras, Hand of Ragnaros") then (yes)
+            :lower quality with 1;
+        else (no)
+        endif
+    else (no)
+    endif
+else (no)
+    if (quality < 50) then (yes)
+        :increase quality with 1;
+    else (no)
+    endif
+endif
+
+if (not "Sulfuras, Hand of Ragnaros") then (yes)
+    :lower sell in with 1;
+else (no)
+endif
+
+if (sell in < 0) then (yes)
+    if (not "Aged Brie") then (yes)
+        if (quality > 0) then (yes)
+            if (not "Sulfuras, Hand of Ragnaros") then (yes)
+                :lower quality with 1;
+            else (no)
+            endif
+        else (no)
+        endif
+    else (no)
+        if (quality < 50) then (yes)
+            :increase quality with 1;
+        else (no)
+        endif
+    endif
+else (no)
+endif
+
+stop
+
+@enduml
diff --git a/plantuml/history/07_backstage-passes.puml b/plantuml/history/07_backstage-passes.puml
new file mode 100644
index 00000000..5d6f2fa3
--- /dev/null
+++ b/plantuml/history/07_backstage-passes.puml
@@ -0,0 +1,68 @@
+@startuml
+
+skinparam backgroundColor transparent
+
+start
+
+if (not "Aged Brie" and not "Backstage passes to a TAFKAL80ETC concert") then (yes)
+    if (quality > 0) then (yes)
+        if (not "Sulfuras, Hand of Ragnaros") then (yes)
+            :lower quality with 1;
+        else (no)
+        endif
+    else (no)
+    endif
+else (no)
+    if (quality < 50) then (yes)
+        :increase quality with 1;
+        if ("Backstage passes to a TAFKAL80ETC concert") then (yes)
+            if (sell in < 11) then (yes)
+                if (quality < 50) then (yes)
+                    :increase quality with 1;
+                else (no)
+                endif
+            else (no)
+            endif
+            if (sell in < 6) then (yes)
+                if (quality < 50) then (yes)
+                    :increase quality with 1;
+                else (no)
+                endif
+            else (no)
+            endif
+        else (no)
+        endif
+    else (no)
+    endif
+endif
+
+if (not "Sulfuras, Hand of Ragnaros") then (yes)
+    :lower sell in with 1;
+else (no)
+endif
+
+if (sell in < 0) then (yes)
+    if (not "Aged Brie") then (yes)
+        if (not "Backstage passes to a TAFKAL80ETC concert") then (yes)
+            if (quality > 0) then (yes)
+                if (not "Sulfuras, Hand of Ragnaros") then (yes)
+                    :lower quality with 1;
+                else (no)
+                endif
+            else (no)
+            endif
+        else (no)
+            :lower quality with quality;
+        endif
+    else (no)
+        if (quality < 50) then (yes)
+            :increase quality with 1;
+        else (no)
+        endif
+    endif
+else (no)
+endif
+
+stop
+
+@enduml
diff --git a/plantuml/readme.md b/plantuml/readme.md
new file mode 100644
index 00000000..9c577adb
--- /dev/null
+++ b/plantuml/readme.md
@@ -0,0 +1,22 @@
+# PlantUML
+This UML refactoring exercise is aimed at less technical people like analysts, testers and other non-programmers. The key takeaway message is clarifying the need for continuous refactoring to people who do not code on a daily basis.
+
+## Running and rendering
+If you want to get started quickly, just copy the contents of `plantuml/gilded-rose.puml`, and paste it in https://www.planttext.com/
+
+Several alternatives are available to render PlantUML, see https://plantuml.com/running.
+
+## Syntax
+For the syntax of activity diagrams in PlantUML, please refer to https://plantuml.com/activity-diagram-beta
+
+## Workshop
+You can run this exercise as a workshop.
+
+During this workshop, you start off with a presentation explaining the domain, while filling out the testcases found under `plantuml/workshop`. After that, participants are invited to refactor the UML Activity Diagram, using the examples that were discovered during the presentation. 
+[The google slides can be found here](https://docs.google.com/presentation/d/1kkRnVQjZELcfuGoFXaiSY_HxbO4lPQnSgHRGQZIH2nU/edit?usp=sharing). 
+
+## History
+If you want to illustrate how this activity diagram got to this state, you can show the requirements and the files under the /history directory. These individual files show the evolution of the activity diagram.
+
+## Original state
+![The original activity diagram](./gilded-rose.png)
diff --git a/plantuml/workshop-materials/testcases.pdf b/plantuml/workshop-materials/testcases.pdf
new file mode 100644
index 00000000..be311e2d
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