diff --git a/resources/public/images/devil.png b/resources/public/images/devil.png
new file mode 100644
index 0000000..839168c
Binary files /dev/null and b/resources/public/images/devil.png differ
diff --git a/src/clj/transducerpres/slides/transducer_function.clj b/src/clj/transducerpres/slides/transducer_function.clj
index 4afa917..3c63f5a 100644
--- a/src/clj/transducerpres/slides/transducer_function.clj
+++ b/src/clj/transducerpres/slides/transducer_function.clj
@@ -2,13 +2,107 @@
     (:require [transducerpres.slides.util :refer [defslide defmarkdownslide markdown-part clj-code python-code img]]))
 
 
-(defmarkdownslide intro-slide
-    "#### transducer functions!!")
+(defslide intro-slide
+    (markdown-part
+        "#### transducer functions!!")
+    (img "devil.png"))
 
-(defslide devil
-    (img "devil.jpg"))
+(defslide we-start-from-where-we-were
+    (markdown-part "#### We start from where we were...")
+    (clj-code
+        "(defn my-map [f coll]"
+        "    (reduce #(conj %1 (f %2)) [] coll))")
+    (clj-code
+        "(defn my-filter [pred coll]"
+        "    (reduce #(if (pred %2) (conj %1 %2) %1) [] coll))")
+    (clj-code
+        "(defn my-mapcat [pred coll]"
+        "    (reduce (fn [r x](reduce conj r (f x))) [] coll))")
+        )
+
+(defslide we-parameterize-conj
+    (markdown-part "#### And we extract the essence of our functions")
+    (clj-code
+        "(defn mapping [f]"
+        "    (fn [step]"
+        "        (fn [res x] (step res (f x)))))")
+    (clj-code
+        "(defn filtering [pred]"
+        "    (fn [step]"
+        "        (fn [res x] (if (pred x) (step res x) res))))")
+    (clj-code
+        "(def cat"
+        "    (fn [step]"
+        "        (fn [res x] (reduce step res x))))")
+    (clj-code
+        "(defn mapcatting [f]"
+        "    (comp cat (mapping f)))"))
+
+(defslide enjoy-writing-our-function-the-same-way
+    (markdown-part "#### And we can now write our functions in the same way")
+    (clj-code
+        "(defn my-map [f coll]"
+        "    (reduce ((mapping f) conj) [] coll))")
+    (clj-code
+        "(defn my-filter [pred coll]"
+        "    (reduce ((filtering pred) conj) [] coll))")
+    (clj-code
+        "(defn my-mapcat [f coll]"
+        "    (reduce ((mapcatting f) conj) [] coll))"))
+
+(defslide note-on-mapcatting
+    (markdown-part "#### Note on mapcat")
+    (markdown-part "we have defined...")
+    (clj-code
+        "(defn mapping [f]"
+        "    (fn [step]"
+        "        (fn [res x] (step res (f x)))))")
+    (clj-code
+        "(def cat"
+        "    (fn [step]"
+        "        (fn [res x] (reduce step res x))))")
+    (clj-code
+        "(defn mapcatting [f]"
+        "    (comp cat (mapping f)))")
+    [:p "for محمد بن موسی خوارزمی sake why is cat applied before map"])
+
+(defslide developping-mapcatting
+    (markdown-part "#### develop mapcattig the reason is trivial")
+    (clj-code
+        "(fn [res x] (reduce mapping-step res x))")
+    (clj-code
+        "(fn [res x] (reduce (fn [res x] (step res (f x))) res x))"))
+
+(defslide composition-for-human
+    (markdown-part "#### but for humans...")
+    (clj-code
+        "(def trans-1"
+        "    (fn [step](fn [res x] (step res (+ 2 x)))))")
+    (clj-code
+        "(def trans-2"
+        "    (fn [step](fn [res x] (step res (* 3 x)))))")
+    (clj-code
+        "(def trans-3"
+        "    (comp trans-1 trans-2))")
+
+    (clj-code
+        "(fn [res x] (fn [res x] (step res (* 3 x))) res (+ 2 x)))"))
+
+(defmarkdownslide what-transducers-can-do
+    "#### So transducers are..."
+    "*  know nothing about the process they modify"
+    "    * reducing functionnality fully encapsulates"
+    "*  may call step 0, 1 or many times"
+    "*  must pass previous result as next r otherwise must know nothing of r"
+    "*  can transform input args")
 
 
 (defslide transducer-function-slides
     intro-slide
-    devil)
+    we-start-from-where-we-were
+    we-parameterize-conj
+    enjoy-writing-our-function-the-same-way
+    note-on-mapcatting
+    developping-mapcatting
+    composition-for-human
+    what-transducers-can-do)