diff --git a/Sound/Tidal/Strategies.hs b/Sound/Tidal/Strategies.hs
--- a/Sound/Tidal/Strategies.hs
+++ b/Sound/Tidal/Strategies.hs
@@ -12,7 +12,6 @@
 import Sound.Tidal.Time
 import Sound.Tidal.Utils
 import qualified Sound.OSC.FD as OSC.FD
-import Sound.OSC.Datum
 
 stutter n t p = stack $ map (\i -> (t * (fromIntegral i)) ~> p) [0 .. (n-1)]
 
@@ -119,14 +118,12 @@
 scale :: (Functor f, Num b) => b -> b -> f b -> f b
 scale from to p = ((+ from) . (* (to-from))) <$> p
 
-
 chop :: Int -> OscPattern -> OscPattern
-chop n p = Pattern $ \a -> concatMap f $ arcCycles a
-     where f a = concatMap chopEvent (arc p a)
-           chopEvent (a,a',v) = map (newEvent v) $ filter ((isIn a') . fst) (chopArc a n)
-           chopArc :: Arc -> Int -> [Arc]
-           chopArc (s, e) n = map (\i -> ((s + d*(fromIntegral i)), s + d*(fromIntegral $ i+1))) [0 .. n-1]
-                   where d = e - s
-           newEvent :: OscMap -> Arc -> Event OscMap
-           newEvent v a = (a,a,Map.insert (param dirt "begin") (Just $ OSC.FD.float 0) v)
+chop n p = Pattern $ \queryA -> concatMap (f queryA) $ arcCycles queryA
+     where f queryA a = concatMap (chopEvent queryA) (arc p a)
+           chopEvent (queryS, queryE) (a,a',v) = map (newEvent v) $ filter (\(_, (s,e)) -> not $ or [e < queryS, s >= queryE]) (enumerate $ chopArc a n)
+           newEvent :: OscMap -> (Int, Arc) -> Event OscMap
+           newEvent v (i, a) = (a,a,Map.insert (param dirt "end") (Just $ OSC.FD.float ((fromIntegral $ i+1)/(fromIntegral n))) $ Map.insert (param dirt "begin") (Just $ OSC.FD.float ((fromIntegral i)/(fromIntegral n))) v)
 
+chopArc :: Arc -> Int -> [Arc]
+chopArc (s, e) n = map (\i -> ((s + (e-s)*(fromIntegral i/fromIntegral n)), s + (e-s)*((fromIntegral $ i+1)/fromIntegral n))) [0 .. n-1]
diff --git a/doc/tidal.md b/doc/tidal.md
--- a/doc/tidal.md
+++ b/doc/tidal.md
@@ -176,17 +176,19 @@
 
 # Tempo
 
-You can change the beats per second (bps) like this:
+You can change the cycles per second (cps) like this:
 
 ~~~~ {.haskell}
-bps 1
+cps 0.5
 ~~~~
 
-If you prefer to think in beats per minute, simply divide by 60
+The above would give a rate of one cycle every two seconds. If you prefer to think in cycles per minute, simply divide by 60:
 
 ~~~~ {.haskell}
-bps (140 / 60)
+cps (30 / 60)
 ~~~~
+
+If you wish to think in terms of 'beats' rather than cycles, then decide how many beats per cycle you expect to work with, and divide accordingly.
 
 # Samples
 
diff --git a/tidal.cabal b/tidal.cabal
--- a/tidal.cabal
+++ b/tidal.cabal
@@ -1,5 +1,5 @@
 name:                tidal
-version:             0.4.9
+version:             0.4.10
 synopsis:            Pattern language for improvised music
 -- description:         
 homepage:            http://yaxu.org/tidal/
diff --git a/tidal.el b/tidal.el
--- a/tidal.el
+++ b/tidal.el
@@ -57,8 +57,8 @@
   (tidal-send-string ":set prompt \"\"")
   (tidal-send-string ":module Sound.Tidal.Context")
 ;  (tidal-send-string "import Volca.Beat")
-  (tidal-send-string "import Volca.Key")
-  (tidal-send-string "(note, [portamento, expression, voice, octave, detune, vcoegint, kcutoff, vcfegint, lforate, lfopitchint, lfocutoffint, attack, decay, sustain, dtime , dfeedback], keystop) <- keystart")
+;  (tidal-send-string "import Volca.Key")
+;  (tidal-send-string "(note, [portamento, expression, voice, octave, detune, vcoegint, kcutoff, vcfegint, lforate, lfopitchint, lfocutoffint, attack, decay, sustain, dtime , dfeedback], keystop) <- keystart")
 ;  (tidal-send-string "(drum, [clapSpeed, clavesSpeed, agogoSpeed, crashSpeed, stutterTime, stutterDepth, tomDecay, clhatDecay, ophatDecay, hatGrain], beatstop) <- startbeat")
   (tidal-send-string "d1 <- dirtStream")
   (tidal-send-string "d2 <- dirtStream")
@@ -136,6 +136,9 @@
   (tidal-send-string "now' <- getNow")
   (tidal-send-string "let now = nextSam now'")
   (tidal-send-string "let retrig = (now ~>)")
+  (tidal-send-string "let fadeOut n = spread' (degradeBy) (retrig $ slow n $ envL)")
+  (tidal-send-string "let fadeIn n = spread' (degradeBy) (retrig $ slow n $ (1-) <$> envL)")
+
   )
 
 (defun tidal-run-line ()