diff --git a/src/com/owoga/corpus/markov.clj b/src/com/owoga/corpus/markov.clj
index 1d11720..35a1fa8 100644
--- a/src/com/owoga/corpus/markov.clj
+++ b/src/com/owoga/corpus/markov.clj
@@ -8,7 +8,8 @@
             [com.owoga.tightly-packed-trie :as tpt]
             [clojure.string :as string]
             [clojure.java.io :as io]
-            [com.owoga.phonetics :as phonetics]))
+            [com.owoga.phonetics :as phonetics]
+            [taoensso.nippy :as nippy]))
 
 (defn clean-text [text]
   (string/lower-case (string/replace text #"[^a-zA-Z'\-\s]" "")))
@@ -294,7 +295,8 @@
     (map (partial transduce data-transform/xf-tokenize conj))
     (map (partial transduce data-transform/xf-filter-english conj))
     (map (partial remove empty?))
-    (map (partial map reverse))
+    (map (partial map (comp vec reverse)))
+    ;; xf-pad-tokens works on vectors due to `into`
     (map (partial into [] (data-transform/xf-pad-tokens (dec m) "</s>" 1 "<s>")))
     (map (partial mapcat (partial data-transform/n-to-m-partitions n (inc m))))
     (mapcat (partial mapv (data-transform/make-database-processor database))))
@@ -332,43 +334,49 @@
 
   )
 
+(defn train-backwards
+  "For building lines backwards so they can be seeded with a target rhyme."
+  [files n m trie-filepath database-filepath]
+  (let [database (atom {:next-id 0})
+        trie (file-seq->backwards-markov-trie database files n m)]
+    (nippy/freeze-to-file trie-filepath (seq trie))
+    (nippy/freeze-to-file database-filepath @database)
+    (let [loaded-trie (->> trie-filepath
+                           nippy/thaw-from-file
+                           (into (trie/make-trie)))
+          loaded-db (->> database-filepath
+                         nippy/thaw-from-file)]
+      (println "Successfully loaded trie and database.")
+      (println (take 5 loaded-trie))
+      (println (take 5 loaded-db)))))
 
+(comment
+  (time
+   (let [files (->> "dark-corpus"
+                    io/file
+                    file-seq
+                    (eduction (xf-file-seq 0 4000)))
+         [trie database] (train-backwards files 1 4 "/tmp/trie.bin" "/tmp/database.bin")]))
+  )
+
+(defn gen-rhyme-model
+  [rhyme-type-fn database database-filepath]
+  (let [words (filter string? (keys @database))
+        rhyme-trie (prhyme/words->rhyme-trie rhyme-type-fn words)]
+    (nippy/freeze-to-file database-filepath (seq rhyme-trie))
+    (let [loaded-trie (->> (nippy/thaw-from-file database-filepath)
+                           (into (trie/make-trie)))]
+      (println "Successfully loaded rhyme model")
+      (println (take 5 loaded-trie)))))
+
+(comment
+  (let [database (atom (nippy/thaw-from-file "/tmp/database.edn"))]
+    (gen-rhyme-model prhyme/phrase->all-flex-rhyme-tailing-consonants-phones database "/tmp/rhyme-trie.bin"))
+  (def rt (into (trie/make-trie) (nippy/thaw-from-file "/tmp/rhyme-trie.bin")))
+
+  (take 5 rt)
 
-(defn initialize
-  "Takes an atom as a context. Swaps in :database, :trie, :rhyme-trie"
-  [context]
-
-  (swap!
-   context
-   assoc
-   :rhyme-trie
-   (transduce
-    (comp
-     (map first)
-     (filter string?)
-     (map (fn [word]
-            (let [phones-coll (phonetics/get-phones)]
-              (map
-               #(vector (reverse (phonetics/get-phones %)) word)
-               phones-coll)))))
-    (completing
-     (fn [trie [k v]]
-       (update trie k (fnil #(update % 1 inc) [v 0]))))
-    (trie/make-trie)
-    (@context :database)))
-
-  (swap!
-   context
-   assoc
-   :flex-rhyme-trie
-   (transduce
-    (comp
-     (map first)
-     (filter string?)
-     (map #(vector (reverse (prhyme/phrase->flex-rhyme-phones %)) %)))
-    (completing
-     (fn [trie [k v]]
-       (update trie k (fnil conj [v]) v)))
-    (trie/make-trie)
-    (@context :database)))
-  nil)
+  (prhyme/phrase->all-flex-rhyme-tailing-consonants-phones "brasilia")
+  (phonetics/get-phones "brasilia")
+
+  )
diff --git a/src/com/owoga/prhyme/core.clj b/src/com/owoga/prhyme/core.clj
index 600727f..4e5b641 100644
--- a/src/com/owoga/prhyme/core.clj
+++ b/src/com/owoga/prhyme/core.clj
@@ -159,6 +159,9 @@
   ;;     ("P") nil}
   )
 
+;;;; Flex rhymes maintain primary stress and ignore all other stress.
+;;;;
+
 (defn phrase->all-flex-rhyme-phones
   "Takes a space-seperated string of words
   and returns the concatenation of the words
@@ -167,7 +170,9 @@
   Returns them in reversed order so they
   are ready to be used in a lookup of a rhyme trie.
 
-  Returns all possible pronunciations. For hog -> haog, haag."
+  Returns all possible pronunciations. For hog -> haog, haag.
+
+  ROBOT -> '(OW1 AA)"
   [phrase]
   (->> phrase
        (#(string/split % #" "))
@@ -216,27 +221,100 @@
   (let [result (map phrase->all-flex-rhyme-phones ["dog" "hog" "hop" "bog hopscotch"])]
     result)
 
-  (let [phrase '(([["B" "AA1" "G"] "bog"] [["B" "AO1" "G"] "bog"])
-                 ([["S" "K" "AA1" "CH"] "scotch"]))]
-    (apply combinatorics/cartesian-product phrase))
+  )
+
+
+(defn vowel?-ignoring-stress
+  [phone]
+  (phonetics/vowel (string/replace phone #"\d" "")))
+
+(defn take-vowels-and-tail-consonants
+  "HOPSCOTCH -> AA1 AA2 CH
+
+  Useful for finding rhymes where the last vowel and tailing consonants
+  are the same and preceding vowels are the same."
+  ([phones]
+   (take-vowels-and-tail-consonants phones '() false))
+  ([phones result taken-vowel?]
+   (cond
+     (empty? phones) result
+     (and taken-vowel? (not (vowel?-ignoring-stress (last phones))))
+     (recur (butlast phones) result taken-vowel?)
+     (vowel?-ignoring-stress (last phones))
+     (recur (butlast phones) (cons (last phones) result) true)
+     :else (recur (butlast phones) (cons (last phones) result) taken-vowel?))))
 
-  (phonetics/get-phones "bog")
+(comment
+  (take-vowels-and-tail-consonants (first (phonetics/get-phones "robot")))
+  ;; => ("OW1" "AA2" "T")
   )
 
-#_(defn phrase->flex-rhyme-trie
+(defn remove-non-primary-stress
+  [phones]
+  (map
+   #(string/replace % #"[02-9]" "")
+   phones))
+
+(defn phrase->all-flex-rhyme-tailing-consonants-phones
+  "Takes a space-seperated string of words
+  and returns the concatenation of the words
+  vowel phones.
+
+  Returns them in reversed order so they
+  are ready to be used in a lookup of a rhyme trie.
+
+  Returns all possible pronunciations. For hog -> haog, haag.
+
+  ROBOT -> '(OW1 AA2 T)"
   [phrase]
-  (transduce
-   (comp
-    (map #(vector (map reverse (phonetics/get-phones %)) %)))
-   (completing
-    (fn [trie [lookups v]]
-      (reduce
-       (fn [trie lookup]
-         (update trie lookup (fnil #(update % 1 inc) [v 0])))
-       trie
-       lookups)))
-   (trie/make-trie)
-   words))
+  (->> phrase
+       (#(string/split % #" "))
+       (map (fn [word]
+              (let [phones (phonetics/get-phones word)]
+                (map #(vector % word) phones))))
+       ;; Lots of nesting here.
+       ;; We have phrase -> word pronunciations -> word pronunciation -> [phones word]
+       ;; The rest will be easier if we get rid of a level of nesting
+       ;; by mapcatting the cross product of pronunciations.
+       (apply combinatorics/cartesian-product)
+       ;; Now we have [phrases [pronunciations [[phones] word]]]
+       (map (partial apply map vector))
+       (map (fn [[phones words]]
+              [(apply concat phones)
+               (string/join " " words)]))
+       (map #(update % 0 take-vowels-and-tail-consonants))
+       (map #(update % 0 remove-non-primary-stress))))
+
+(comment
+  (phrase->all-flex-rhyme-tailing-consonants-phones "robot")
+  ;; => ([("OW1" "AA" "T") "robot"] [("OW1" "AH" "T") "robot"])
+  )
+
+
+(defn words->rhyme-trie
+  [rhyme-type-fn words]
+  (->> words
+       (mapcat rhyme-type-fn)
+       (map #(update % 0 reverse))
+       (reduce
+        (fn [trie [phones word]]
+          (update trie phones conj word))
+        (trie/make-trie))))
+
+
+(comment
+  (let [words ["tightnit" "tarpit"]
+        trie (words->rhyme-trie phrase->all-flex-rhyme-tailing-consonants-phones words)]
+    (->> (trie/lookup trie ["AA"]))
+    trie)
+  ;; => {("T" "IH1" "AA") ("tarpit"),
+  ;;     ("T" "IH1" "AY1") ("tightnit"),
+  ;;     ("T" "IH1") nil,
+  ;;     ("T") nil}
+
+  )
+
+
 
 (defn phrase->flex-rhyme-phones
   "Takes a space-seperated string of words
diff --git a/src/com/owoga/prhyme/data_transform.clj b/src/com/owoga/prhyme/data_transform.clj
index 3ff5a60..b99ccfa 100644
--- a/src/com/owoga/prhyme/data_transform.clj
+++ b/src/com/owoga/prhyme/data_transform.clj
@@ -116,7 +116,7 @@
                             id
                             (new-key database key)))
                         lookup)]
-      [lookup' v])))
+      lookup')))
 
 (comment
   ;; TODO: Move to nlp.core