diff --git a/part10/ElmHub.elm b/part10/ElmHub.elm
index 6300c50..1af4bc5 100644
--- a/part10/ElmHub.elm
+++ b/part10/ElmHub.elm
@@ -1,7 +1,7 @@
 module ElmHub (..) where
 
 import Html exposing (..)
-import Html.Attributes exposing (..)
+import Html.Attributes exposing (class, target, href, property)
 import Html.Events exposing (..)
 import Html.Lazy exposing (..)
 import Http
diff --git a/part12/Component/ElmHub.elm b/part12/ElmHub.elm
similarity index 53%
rename from part12/Component/ElmHub.elm
rename to part12/ElmHub.elm
index 8bf3f90..89e2a17 100644
--- a/part12/Component/ElmHub.elm
+++ b/part12/ElmHub.elm
@@ -1,4 +1,4 @@
-module Component.ElmHub (..) where
+module ElmHub (..) where
 
 import Html exposing (..)
 import Html.Attributes exposing (..)
@@ -11,7 +11,8 @@ import Effects exposing (Effects)
 import Json.Decode exposing (Decoder, (:=))
 import Json.Encode
 import Signal exposing (Address)
-import Component.SearchResult exposing (ResultId)
+import Dict exposing (Dict)
+import SearchResult exposing (ResultId)
 
 
 searchFeed : String -> Task x Action
@@ -32,31 +33,21 @@ searchFeed query =
     Task.onError task (\_ -> Task.succeed (SetResults []))
 
 
-responseDecoder : Decoder (List Component.SearchResult.Model)
+responseDecoder : Decoder (List SearchResult.Model)
 responseDecoder =
-  "items" := Json.Decode.list searchResultDecoder
-
-
-searchResultDecoder : Decoder Component.SearchResult.Model
-searchResultDecoder =
-  Json.Decode.object4
-    Component.SearchResult.Model
-    ("id" := Json.Decode.int)
-    ("full_name" := Json.Decode.string)
-    ("stargazers_count" := Json.Decode.int)
-    (Json.Decode.succeed True)
+  "items" := Json.Decode.list SearchResult.decoder
 
 
 type alias Model =
   { query : String
-  , results : List Component.SearchResult.Model
+  , results : Dict SearchResult.ResultId SearchResult.Model
   }
 
 
 initialModel : Model
 initialModel =
   { query = "tutorial"
-  , results = []
+  , results = Dict.empty
   }
 
 
@@ -77,24 +68,19 @@ view address model =
     ]
 
 
-viewSearchResults : Address Action -> List Component.SearchResult.Model -> List Html
+viewSearchResults : Address Action -> Dict ResultId SearchResult.Model -> List Html
 viewSearchResults address results =
   results
-    |> filterResults
-    |> List.map (lazy2 viewSearchResult address)
+    |> Dict.values
+    |> List.sortBy (.stars >> negate)
+    |> List.map (viewSearchResult address)
 
 
-filterResults : List Component.SearchResult.Model -> List Component.SearchResult.Model
-filterResults results =
-  case results of
-    [] ->
-      []
-
-    first :: rest ->
-      if first.stars > 0 then
-        first :: (filterResults rest)
-      else
-        filterResults rest
+viewSearchResult : Address Action -> SearchResult.Model -> Html
+viewSearchResult address result =
+  SearchResult.view
+    (Signal.forwardTo address (UpdateSearchResult result.id))
+    result
 
 
 onInput address wrap =
@@ -105,18 +91,11 @@ defaultValue str =
   property "defaultValue" (Json.Encode.string str)
 
 
-viewSearchResult : Address Action -> Component.SearchResult.Model -> Html
-viewSearchResult address result =
-  Component.SearchResult.view
-    (Signal.forwardTo address (UpdateSearchResult result.id))
-    (Debug.log "rendering result..." result)
-
-
 type Action
   = Search
   | SetQuery String
-  | SetResults (List Component.SearchResult.Model)
-  | UpdateSearchResult ResultId Component.SearchResult.Action
+  | SetResults (List SearchResult.Model)
+  | UpdateSearchResult ResultId SearchResult.Action
 
 
 update : Action -> Model -> ( Model, Effects Action )
@@ -130,31 +109,31 @@ update action model =
 
     SetResults results ->
       let
-        newModel =
-          { model | results = results }
+        resultsById : Dict SearchResult.ResultId SearchResult.Model
+        resultsById =
+          results
+            |> List.map (\result -> ( result.id, result ))
+            |> Dict.fromList
       in
-        ( newModel, Effects.none )
+        ( { model | results = resultsById }, Effects.none )
 
     UpdateSearchResult id childAction ->
       let
-        updateResult childModel =
-          if childModel.id == id then
-            let
-              ( newChildModel, childEffects ) =
-                Component.SearchResult.update childAction childModel
-            in
-              ( newChildModel
-              , Effects.map (UpdateSearchResult id) childEffects
-              )
-          else
-            ( childModel, Effects.none )
-
-        ( newResults, effects ) =
+        updated =
           model.results
-            |> List.map updateResult
-            |> List.unzip
-
-        newModel =
-          { model | results = newResults }
+            |> Dict.get id
+            |> Maybe.map (SearchResult.update childAction)
       in
-        ( newModel, Effects.batch effects )
+        case updated of
+          Nothing ->
+            ( model, Effects.none )
+
+          Just ( newChildModel, childEffects ) ->
+            let
+              effects =
+                Effects.map (UpdateSearchResult id) childEffects
+
+              newResults =
+                Dict.insert id newChildModel model.results
+            in
+              ( { model | results = newResults }, effects )
diff --git a/part12/Main.elm b/part12/Main.elm
index 5b8e88e..fa4bada 100644
--- a/part12/Main.elm
+++ b/part12/Main.elm
@@ -1,7 +1,7 @@
 module Main (..) where
 
 import StartApp
-import Component.ElmHub exposing (..)
+import ElmHub exposing (..)
 import Effects exposing (Effects)
 import Task exposing (Task)
 import Html exposing (Html)
diff --git a/part12/README.md b/part12/README.md
index deddbd0..f597959 100644
--- a/part12/README.md
+++ b/part12/README.md
@@ -15,3 +15,7 @@ to fail; in that case, just run `elm package install` again.)
 ```bash
 elm live Main.elm --open -- --output=elm.js
 ```
+
+## References
+
+* [Elm Architecture Tutorial](https://github.com/evancz/elm-architecture-tutorial)
diff --git a/part12/Component/SearchResult.elm b/part12/SearchResult.elm
similarity index 69%
rename from part12/Component/SearchResult.elm
rename to part12/SearchResult.elm
index 4dedbd3..2d1256d 100644
--- a/part12/Component/SearchResult.elm
+++ b/part12/SearchResult.elm
@@ -1,10 +1,12 @@
-module Component.SearchResult (..) where
+module SearchResult (..) where
 
 import Html exposing (..)
-import Html.Attributes exposing (..)
+import Html.Attributes exposing (class, target, href, property)
 import Html.Events exposing (..)
 import Signal exposing (Address)
 import Effects exposing (Effects)
+import Json.Decode exposing (Decoder, (:=))
+import Json.Decode.Pipeline exposing (..)
 
 
 type alias Model =
@@ -24,9 +26,18 @@ type Action
   | Collapse
 
 
+decoder : Decoder Model
+decoder =
+  decode Model
+    |> required "id" Json.Decode.int
+    |> required "full_name" Json.Decode.string
+    |> required "stargazers_count" Json.Decode.int
+    |> hardcoded True
+
+
 update : Action -> Model -> ( Model, Effects Action )
 update action model =
-  -- TODO make expand and collapse work
+  -- TODO implement Expand and Collapse logic
   ( model, Effects.none )
 
 
diff --git a/part12/elm-package.json b/part12/elm-package.json
index ba40466..f4a6d00 100644
--- a/part12/elm-package.json
+++ b/part12/elm-package.json
@@ -4,10 +4,12 @@
     "repository": "https://github.com/rtfeldman/elm-workshop.git",
     "license": "BSD-3-Clause",
     "source-directories": [
-        ".", ".."
+        ".",
+        ".."
     ],
     "exposed-modules": [],
     "dependencies": {
+        "NoRedInk/elm-decode-pipeline": "1.0.0 <= v < 2.0.0",
         "elm-lang/core": "3.0.0 <= v < 4.0.0",
         "evancz/elm-effects": "2.0.0 <= v < 3.0.0",
         "evancz/elm-html": "4.0.0 <= v < 5.0.0",
@@ -15,4 +17,4 @@
         "evancz/start-app": "2.0.0 <= v < 3.0.0"
     },
     "elm-version": "0.16.0 <= v < 0.17.0"
-}
+}
\ No newline at end of file
diff --git a/part13/ElmHub.elm b/part13/ElmHub.elm
index 8476dbf..89e2a17 100644
--- a/part13/ElmHub.elm
+++ b/part13/ElmHub.elm
@@ -12,7 +12,7 @@ import Json.Decode exposing (Decoder, (:=))
 import Json.Encode
 import Signal exposing (Address)
 import Dict exposing (Dict)
-import SearchResult
+import SearchResult exposing (ResultId)
 
 
 searchFeed : String -> Task x Action
@@ -68,26 +68,19 @@ view address model =
     ]
 
 
-viewSearchResults : Address Action -> Dict SearchResult.ResultId SearchResult.Model -> List Html
+viewSearchResults : Address Action -> Dict ResultId SearchResult.Model -> List Html
 viewSearchResults address results =
   results
     |> Dict.values
     |> List.sortBy (.stars >> negate)
-    |> filterResults
-    |> List.map (lazy3 SearchResult.view address DeleteById)
+    |> List.map (viewSearchResult address)
 
 
-filterResults : List SearchResult.Model -> List SearchResult.Model
-filterResults results =
-  case results of
-    [] ->
-      []
-
-    result :: rest ->
-      if result.stars > 0 then
-        result :: (filterResults rest)
-      else
-        filterResults rest
+viewSearchResult : Address Action -> SearchResult.Model -> Html
+viewSearchResult address result =
+  SearchResult.view
+    (Signal.forwardTo address (UpdateSearchResult result.id))
+    result
 
 
 onInput address wrap =
@@ -101,8 +94,8 @@ defaultValue str =
 type Action
   = Search
   | SetQuery String
-  | DeleteById SearchResult.ResultId
   | SetResults (List SearchResult.Model)
+  | UpdateSearchResult ResultId SearchResult.Action
 
 
 update : Action -> Model -> ( Model, Effects Action )
@@ -124,9 +117,23 @@ update action model =
       in
         ( { model | results = resultsById }, Effects.none )
 
-    DeleteById id ->
+    UpdateSearchResult id childAction ->
       let
-        newModel =
-          { model | results = Dict.remove id model.results }
+        updated =
+          model.results
+            |> Dict.get id
+            |> Maybe.map (SearchResult.update childAction)
       in
-        ( newModel, Effects.none )
+        case updated of
+          Nothing ->
+            ( model, Effects.none )
+
+          Just ( newChildModel, childEffects ) ->
+            let
+              effects =
+                Effects.map (UpdateSearchResult id) childEffects
+
+              newResults =
+                Dict.insert id newChildModel model.results
+            in
+              ( { model | results = newResults }, effects )
diff --git a/part13/SearchResult.elm b/part13/SearchResult.elm
index daf012a..5099bfd 100644
--- a/part13/SearchResult.elm
+++ b/part13/SearchResult.elm
@@ -1,44 +1,65 @@
 module SearchResult (..) where
 
 import Html exposing (..)
-import Html.Attributes exposing (..)
+import Html.Attributes exposing (class, target, href, property)
 import Html.Events exposing (..)
-import Json.Decode exposing (Decoder, (:=))
 import Signal exposing (Address)
-import Dict exposing (Dict)
+import Effects exposing (Effects)
+import Json.Decode exposing (Decoder, (:=))
+import Json.Decode.Pipeline exposing (..)
+
+
+type alias Model =
+  { id : Int
+  , name : String
+  , stars : Int
+  , expanded : Bool
+  }
 
 
 type alias ResultId =
   Int
 
 
-type alias Model =
-  { id : ResultId
-  , name : String
-  , stars : Int
-  }
+type Action
+  = Expand
+  | Collapse
 
 
 decoder : Decoder Model
 decoder =
-  Json.Decode.object3
-    Model
-    ("id" := Json.Decode.int)
-    ("full_name" := Json.Decode.string)
-    ("stargazers_count" := Json.Decode.int)
+  decode Model
+    |> required "id" Json.Decode.int
+    |> required "full_name" Json.Decode.string
+    |> required "stargazers_count" Json.Decode.int
+    |> hardcoded True
 
 
-view : Address a -> (Int -> a) -> Model -> Html
-view address delete result =
+update : Action -> Model -> ( Model, Effects Action )
+update action model =
+  case action of
+    Expand ->
+      ( { model | expanded = True }, Effects.none )
+
+    Collapse ->
+      ( { model | expanded = False }, Effects.none )
+
+
+view : Address Action -> Model -> Html
+view address model =
   li
     []
-    [ span [ class "star-count" ] [ text (toString result.stars) ]
-    , a
-        [ href ("https://github.com/" ++ result.name)
-        , target "_blank"
+    <| if model.expanded then
+        [ span [ class "star-count" ] [ text (toString model.stars) ]
+        , a
+            [ href ("https://github.com/" ++ model.name), target "_blank" ]
+            [ text model.name ]
+        , button
+            [ class "hide-result", onClick address Collapse ]
+            [ text "X" ]
+        ]
+       else
+        [ button
+            [ class "expand-result", onClick address Expand ]
+            [ text "Show" ]
         ]
-        [ text result.name ]
-    , button
-        [ class "hide-result", onClick address (delete result.id) ]
-        [ text "X" ]
-    ]
diff --git a/part13/style.css b/part13/style.css
index 9d13aae..d030733 100644
--- a/part13/style.css
+++ b/part13/style.css
@@ -1,6 +1,101 @@
+
 .content {
-    width: 960px;
-    margin: 0 auto;
-    padding: 30px;
-    font-family: Helvetica, Arial, serif;
+  width: 960px;
+  margin: 0 auto;
+  padding: 30px;
+  font-family: Helvetica, Arial, serif;
+}
+
+header {
+  position: relative;
+  padding: 6px 12px;
+  height: 36px;
+  background-color: rgb(96, 181, 204);
+}
+
+h1 {
+  color: white;
+  font-weight: normal;
+  margin: 0;
+}
+
+.tagline {
+  color: #eee;
+  position: absolute;
+  right: 16px;
+  top: 12px;
+  font-size: 24px;
+  font-style: italic;
+}
+
+.results {
+  list-style-image: url('http://img-cache.cdn.gaiaonline.com/76bd5c99d8f2236e9d3672510e933fdf/http://i278.photobucket.com/albums/kk81/d3m3nt3dpr3p/Tiny-Star-Icon.png');
+  list-style-position: inside;
+  padding: 0;
+}
+
+.results li {
+  font-size: 18px;
+  margin-bottom: 16px;
+}
+
+.star-count {
+  font-weight: bold;
+  margin-right: 16px;
+}
+
+a {
+  color: rgb(96, 181, 204);
+  text-decoration: none;
+}
+
+a:hover {
+  text-decoration: underline;
+}
+
+.search-query {
+  padding: 8px;
+  font-size: 24px;
+  margin-bottom: 18px;
+  margin-top: 36px;
+}
+
+.search-button {
+  padding: 8px 16px;
+  font-size: 24px;
+  color: white;
+  border: 1px solid #ccc;
+  background-color: rgb(96, 181, 204);
+  margin-left: 12px
+}
+
+.search-button:hover {
+  color: rgb(96, 181, 204);
+  background-color: white;
+}
+
+.hide-result {
+  background-color: transparent;
+  border: 0;
+  font-weight: bold;
+  font-size: 18px;
+  margin-left: 18px;
+  cursor: pointer;
+}
+
+.hide-result:hover {
+  color: rgb(96, 181, 204);
+}
+
+button:focus, input:focus {
+  outline: none;
+}
+
+.error {
+  background-color: #FF9632;
+  padding: 20px;
+  box-sizing: border-box;
+  overflow-x: auto;
+  font-family: monospace;
+  font-size: 18px;
 }