diff --git a/learning-hmm.cabal b/learning-hmm.cabal
--- a/learning-hmm.cabal
+++ b/learning-hmm.cabal
@@ -1,5 +1,5 @@
 name:                learning-hmm
-version:             0.1.1.0
+version:             0.1.1.1
 stability:           experimental
 
 synopsis:            Yet another library for hidden Markov models
diff --git a/src/Learning/HMM.hs b/src/Learning/HMM.hs
--- a/src/Learning/HMM.hs
+++ b/src/Learning/HMM.hs
@@ -135,7 +135,7 @@
   where
     sim _ 0 = return []
     sim s t = do s' <- sample $ rvar $ w s
-                 x' <- sample $ rvar $ phi s
+                 x' <- sample $ rvar $ phi s'
                  ((s', x') :) <$> sim s' (t - 1)
     pi0 = initialStateDist model
     w   = transitionDist model