diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7ebe07a
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,20 @@
+/target
+/classes
+/checkouts
+profiles.clj
+pom.xml
+pom.xml.asc
+*~
+*.jar
+*.class
+/.lein-*
+/.nrepl-port
+/.prepl-port
+.hgignore
+.hg/
+.clj-kondo/
+.lsp/
+.portal/
+.calva/output-window/output.calva-repl
+
+dengine.code-workspace
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..ad1cf3f
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,24 @@
+# Change Log
+All notable changes to this project will be documented in this file. This change log follows the conventions of [keepachangelog.com](http://keepachangelog.com/).
+
+## [Unreleased]
+### Changed
+- Add a new arity to `make-widget-async` to provide a different widget shape.
+
+## [0.1.1] - 2025-08-03
+### Changed
+- Documentation on how to make the widgets.
+
+### Removed
+- `make-widget-sync` - we're all async, all the time.
+
+### Fixed
+- Fixed widget maker to keep working when daylight savings switches over.
+
+## 0.1.0 - 2025-08-03
+### Added
+- Files from the new template.
+- Widget maker public API - `make-widget-sync`.
+
+[Unreleased]: https://sourcehost.site/your-name/dengine/compare/0.1.1...HEAD
+[0.1.1]: https://sourcehost.site/your-name/dengine/compare/0.1.0...0.1.1
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..2315126
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,280 @@
+Eclipse Public License - v 2.0
+
+    THE ACCOMPANYING PROGRAM IS PROVIDED UNDER THE TERMS OF THIS ECLIPSE
+    PUBLIC LICENSE ("AGREEMENT"). ANY USE, REPRODUCTION OR DISTRIBUTION
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+Exhibit A - Form of Secondary Licenses Notice
+
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+Secondary Licenses when the conditions for such availability set forth
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+  Simply including a copy of this Agreement, including this Exhibit A
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+
+  If it is not possible or desirable to put the notice in a particular
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diff --git a/doc/intro.md b/doc/intro.md
new file mode 100644
index 0000000..406a689
--- /dev/null
+++ b/doc/intro.md
@@ -0,0 +1,3 @@
+# Introduction to dengine
+
+TODO: write [great documentation](http://jacobian.org/writing/what-to-write/)
diff --git a/project.clj b/project.clj
new file mode 100644
index 0000000..8255e37
--- /dev/null
+++ b/project.clj
@@ -0,0 +1,8 @@
+(defproject dengine "0.1.0-SNAPSHOT"
+  :description "FIXME: write description"
+  :url "http://example.com/FIXME"
+  :license {:name "EPL-2.0 OR GPL-2.0-or-later WITH Classpath-exception-2.0"
+            :url "https://www.eclipse.org/legal/epl-2.0/"}
+  :dependencies [[org.clojure/clojure "1.11.1"]
+                 [org.clojure/clojure "1.12.0"]]
+  :repl-options {:init-ns arboretum.dengine.core})
diff --git a/src/arboretum/dengine/case.clj b/src/arboretum/dengine/case.clj
new file mode 100644
index 0000000..bb75613
--- /dev/null
+++ b/src/arboretum/dengine/case.clj
@@ -0,0 +1,10 @@
+(ns arboretum.dengine.case
+  (:require [arboretum.dengine.protocols :refer [Case]]))
+
+(defrecord CaseImpl [ id  name knowledge]
+  Case
+  (id [this] :foo);;(:id this))
+  (name [this] "foo") ;;(or (:name this) (clojure.core/name (:id this))))
+  (knowledge [this] (:knowledge this))
+  (is? [this feature-id] ((:knowledge this) feature-id))
+  )
\ No newline at end of file
diff --git a/src/arboretum/dengine/core.clj b/src/arboretum/dengine/core.clj
new file mode 100644
index 0000000..5e491d9
--- /dev/null
+++ b/src/arboretum/dengine/core.clj
@@ -0,0 +1,14 @@
+(ns arboretum.dengine.core
+  ;; (:require [arboretum.dengine.feature :refer [decide explain]]
+  ;;           [arboretum.dengine.protocols :refer [proposition]])
+  )
+
+(defn foo
+  "I don't do a whole lot."
+  [x]
+  (println x "Hello, World!"))
+
+;; (defn is? 
+;;   [feature case kb]
+;;   (let [evaluation (decide feature case kb)]
+;;     ((proposition feature) evaluation)))
diff --git a/src/arboretum/dengine/feature.clj b/src/arboretum/dengine/feature.clj
new file mode 100644
index 0000000..1b19bbc
--- /dev/null
+++ b/src/arboretum/dengine/feature.clj
@@ -0,0 +1,35 @@
+(ns arboretum.dengine.feature
+  (:require [arboretum.dengine.kb :refer [!kb]]
+            [arboretum.dengine.protocols :refer [Case Feature Node]]
+            [arboretum.dengine.utils :refer [string->keyword]]
+            [clojure.spec.alpha :as spec]))
+
+(spec/def :arboretum.dengine.feature/name string?)
+
+(spec/def :arboretum.dengine.feature/default boolean?)
+
+(defn- dengine [this c]
+  (let [c' (if (satisfies? Case c) c (-> @!kb :cases c))]
+    (when (nil? c') (throw (ex-info "Unknown or invalid case"
+                                    {:case-identifier c})))
+    (if (:rootnode this)
+      (when-not (satisfies? Node (:rootnode this))
+        (throw (ex-info "Invalid DTree node"
+                        {:node (:rootnode this)
+                         :context this})))
+      (first
+       (filter boolean?
+               (map #(.evaluate % c)
+                    (-> this :rootnode :children)))))))
+
+(defrecord FeatureImpl [^String proposition ^boolean default rootnode]
+  Feature
+  (decide [this c] (let [v ((.id this) c)]
+                     (cond (boolean? v) v
+                           (:rootnode this) (dengine (:rootnode this) c)
+                           :else (:default this))))
+  (default [this] (:default this))
+  (id [this] (string->keyword (:proposition this)))
+  (rootnode [this] (:rootnode this))
+  (proposition [this] (:proposition this)))
+
diff --git a/src/arboretum/dengine/kb.clj b/src/arboretum/dengine/kb.clj
new file mode 100644
index 0000000..3e7e2ce
--- /dev/null
+++ b/src/arboretum/dengine/kb.clj
@@ -0,0 +1,44 @@
+(ns arboretum.dengine.kb
+  (:require
+   arboretum.dengine.case
+   [arboretum.dengine.protocols :refer [Case Feature Kb]]
+   [arboretum.dengine.utils :refer [string->keyword]]
+   [clojure.pprint :refer [pprint]])
+  (:import
+   [arboretum.dengine.case CaseImpl]))
+
+(defrecord KBImpl [cases features]
+  Kb
+  (cases [this] (:cases this))
+  (features [this] (:features this))
+  (get-case [this case-id] (-> this :cases case-id))
+  (get-feature [this feature-id] (-> this :features feature-id))
+  (is? [this case-or-id feature-or-id]
+    (let [c (if (satisfies? Case case-or-id) 
+              case-or-id (-> this :cases case-or-id))
+          f (if (satisfies? Feature feature-or-id) feature-or-id 
+                (-> this :features feature-or-id))]
+      (-> c (:id f)))))
+
+(def !kb
+  "The one instance of the knowledge base."
+  (atom (KBImpl. nil nil)))
+
+(defn add-case
+  "Add a case to the knowledge base with this `name`, and, if supplied, this `id`."
+  ([^String name]
+  (add-case name (string->keyword name (map :id (.cases @!kb)))))
+  ([^String name ^clojure.lang.Keyword id]
+   (let [c (CaseImpl. id name {})]
+    (swap! !kb update-in :cases conj c))))
+
+(defn persist [filepath] 
+  (let [p (if (empty? filepath) "kb.edn" filepath)]
+                                (spit p (with-out-str (pprint @!kb)))))
+(defn restore [filepath] 
+  (let [p (if (empty? filepath) "kb.edn" filepath)
+        kb (read-string (slurp p))]
+    (if (satisfies? Kb kb) (reset! !kb kb)
+        (throw (ex-info "Not a knowledge base?" {:filepath filepath
+                                                :kb kb
+                                                :type (type kb)})))))
\ No newline at end of file
diff --git a/src/arboretum/dengine/node.clj b/src/arboretum/dengine/node.clj
new file mode 100644
index 0000000..5c1a1e8
--- /dev/null
+++ b/src/arboretum/dengine/node.clj
@@ -0,0 +1,12 @@
+(ns arboretum.dengine.node
+  (:require [arboretum.dengine.protocols :refer [Node]]
+            [clojure.spec.alpha :as spec]))
+
+(defrecord NodeImpl [children ^Boolean colour feature ^String fragment]
+           Node
+  (children [this] "The children of this node" (:children this))
+  (colour ^Boolean [this] "The colour of this node" (:colour this))
+  (feature [this] "The feature at this node" (:feature this))
+  (fragment ^String [this] "The explanation fragment at this node")
+  (evaluate [this case-id] )
+  )
\ No newline at end of file
diff --git a/src/arboretum/dengine/protocols.clj b/src/arboretum/dengine/protocols.clj
new file mode 100644
index 0000000..87660e1
--- /dev/null
+++ b/src/arboretum/dengine/protocols.clj
@@ -0,0 +1,70 @@
+(ns arboretum.dengine.protocols
+  (:require [clojure.spec.alpha :as spec]))
+
+;;(declare node?)
+
+;; Design problem here is that the structure of a feature optionally contains
+;; a node, and the structure of a node necessarily containt a feature; but two
+;; clojure namespaces cannot depend on one another.
+
+(defprotocol Case
+  "A case to be decided. It represents an object-in-the-world about
+    which knowledge may be held and enquiries may be made."
+  (id ^Keyword [this] "Returns the `:id` of this case.")
+  (name ^String [this] "Returns the name associated with this case")
+  (knowledge ^APersistentMap [this] "Returns a map whose keys are ids of features 
+                                     and whose values are the values of those 
+                                     features in this case.")
+  (is? ^Boolean [this feature-id] "Returns `true` if feature-id true of `this`,
+                                     `false` if it's definitely not true, and
+                                     `nil` if its truth value is unknown."))
+
+(defmacro case?
+  "Return `true` if this `obj` appears to be a valid case.
+   
+   **NOTE THAT** this does not verify that every key is the id of some feature
+   konwn to the knowledge base."
+  [obj]
+  `(satisfies? Case ~obj))
+
+(defprotocol Feature
+  "A feature has three essential elements: a proposition, a default value, and
+    a method of decision"
+  (decide ^Boolean [this case] "Returns the default value of my proposition for this `case`.
+                                
+                                `case` should be either an object which satisfies the `Case`
+                                protocol or else a keyword, in which case it should be the
+                                key of some case in the global `kb`.")
+  (default ^Boolean [this] "Returns the default value of my proposition")
+  (id ^Keyword [this] "Returns a keywordised representation of the proposition of this feature")
+  (proposition ^String [this] "Returns the proposition associated with this feature")
+  (rootnode [this] "Returns the root node of the dtree for this feature, if one exists, else `nil`"))
+
+(defmacro feature?
+  [obj]
+  `(satisfies? Feature ~obj))
+
+(defprotocol Kb
+  ;; "The knowledge base"
+  (get-case ^APersistentMap [this ^Keyword id] 
+    "Return the case with this `id` from among my cases,
+     if present, else `nil`")
+  (cases ^APersistentMap [this] 
+    "All cases known in this knowledge base, keyed by `:id`")
+  (get-feature ^APersistentMap [this id-or-prop] 
+    "Return the feature with this `id` from among my features,
+     if present, else `nil`")
+  (features ^APersistentMap [this] 
+    "All features known in this knowledge base, keyed by `:proposition`")
+  (is? ^Boolean [this case-or-id feature-or-id] 
+    "Is the feature identified by `feature-or-id` true of the case identified 
+     by `case-or-id?"))
+
+(defprotocol Node
+  "A node in a DTree"
+  (children [this] "The children of this node")
+  (colour ^Boolean [this] "The colour of this node")
+  (feature [this] "The feature at this node")
+  (fragment ^String [this] "The explanation fragment at this node")
+  (evaluate [this case-id] "evaluate this node in the context of the case identified by `case-id`.")
+  (explain [this case-id] "return an explanation from this node or its children for the case identified by `case-id`"))
\ No newline at end of file
diff --git a/src/arboretum/dengine/utils.clj b/src/arboretum/dengine/utils.clj
new file mode 100644
index 0000000..33b4022
--- /dev/null
+++ b/src/arboretum/dengine/utils.clj
@@ -0,0 +1,17 @@
+(ns arboretum.dengine.utils
+  (:require
+   [clojure.string :refer [lower-case replace]]) 
+  (:import
+   [clojure.lang PersistentHashSet]))
+
+(defn string->keyword 
+  "Produce a keyword based on this `s`. If `others` are supplied, the return
+   value will be different from any of those others."
+  ([^String s]
+  (let [x (replace 
+           (replace (lower-case s) #"[^]a-z0-9- ]" "")
+           #" " "-")]
+    (keyword (if (empty? x) (gensym) x))))
+  ([^String s ^PersistentHashSet others]
+   (let [c (string->keyword s)]
+     (if (others c) (keyword (gensym (name c))) c))))
diff --git a/test/dengine/feature_test.clj b/test/dengine/feature_test.clj
new file mode 100644
index 0000000..6bf4f07
--- /dev/null
+++ b/test/dengine/feature_test.clj
@@ -0,0 +1,20 @@
+(ns dengine.feature-test
+   (:require [clojure.test :refer [deftest is testing]]
+            [arboretum.dengine.feature :refer :all])
+  (:import [arboretum.dengine.feature FeatureImpl]))
+
+(deftest feature-impl-test
+      (testing "Testing feature implementation"
+        (let [f (FeatureImpl. "Is entitled to Widow's Allowance" false nil)]
+          (let [expected :is-entitled-to-widows-allowance
+                actual (.id f)]
+            (is (= actual expected)))
+          (let [expected false
+                actual (.default f)]
+            (is (= actual expected)))
+          (let [expected false
+                actual (.decide f {})]
+            (is (= actual expected) "If we have no knoledge and no decision method, take the defualt."))
+          (let [expected false
+                actual (.decide f {:is-entitled-to-widows-benefit true})]
+            (is (= actual expected) "If we have knoledge, return it."))))) 
\ No newline at end of file
diff --git a/test/dengine/kb_test.clj b/test/dengine/kb_test.clj
new file mode 100644
index 0000000..250dde7
--- /dev/null
+++ b/test/dengine/kb_test.clj
@@ -0,0 +1,26 @@
+(ns dengine.kb-test
+  (:require [clojure.test :refer [deftest is testing]]
+            arboretum.dengine.case
+            arboretum.dengine.feature
+            [arboretum.dengine.kb :refer :all])
+  (:import [arboretum.dengine.case CaseImpl]
+           [arboretum.dengine.feature FeatureImpl]
+           [arboretum.dengine.kb KBImpl]))
+
+(def testkb (KBImpl. [(CaseImpl. :case_1 "Mrs Nora Trellis" {:married true :divorced false})] 
+                     [(FeatureImpl. "is entitled to Widow's Benefit" false nil)]))
+
+(reset! !kb testkb)
+
+(deftest access-test
+  (testing "Accessing knowledge in the knowledge base"
+    (let [expected nil
+          actual (.is? testkb :case_1 :widowed)]
+      (is (= actual expected)))
+    (let [expected true
+          actual (.is? testkb :case_1 :married)]
+      (is (= actual expected)))
+    (let [expected false
+          actual (.is? testkb :case_1 :divorced)]
+      (is (= actual expected)))
+    ))
\ No newline at end of file
diff --git a/test/dengine/utils_test.clj b/test/dengine/utils_test.clj
new file mode 100644
index 0000000..81b64aa
--- /dev/null
+++ b/test/dengine/utils_test.clj
@@ -0,0 +1,16 @@
+(ns dengine.utils-test
+  (:require [clojure.test :refer [deftest is testing]]
+            [arboretum.dengine.utils :refer [string->keyword]]))
+
+
+(deftest string-to-keyword-test
+  (testing "string->keyword"
+    (let [s "Entitled to Widow's Benefit"
+          expected :entitled-to-widows-benefit
+          actual (string->keyword s)]
+      (is (= actual expected)))
+     (let [s "Entitled to Widow's Benefit"
+       expected :entitled-to-widows-benefit
+       actual (string->keyword s)]
+   (is (= actual expected)))
+   ))
\ No newline at end of file