diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -28,4 +28,11 @@
 sudo apt-get install -y python3-matplotlib python3-numpy python-mpltoolkits.basemap
 ```
 
-If you have instructions for other machines or OSes let me know.
+If you have instructions for other machines or OSes let me know. We require
+`/usr/bin/python3` to be available; the path isn't configurable right now.
+
+Once you have the prerequisites you can install using the standard incantation
+
+```bash
+cabal install matplotlib
+```
diff --git a/matplotlib.cabal b/matplotlib.cabal
--- a/matplotlib.cabal
+++ b/matplotlib.cabal
@@ -1,7 +1,14 @@
 name:                matplotlib
-version:             0.2.0
+version:             0.2.1
 synopsis:            Bindings to Matplotlib; a Python plotting library
-description:         Matplotlib is probably the most full featured plotting library out there. These bindings provide a quick, easy, and extensible way to use it in Haskell. Type-safety is largely non-existent and sacrificed for maximum extensibility.
+description:
+    Matplotlib is probably the most full featured plotting library out there.
+    These bindings provide a quick, easy, and extensible way to use it in
+    Haskell.
+    .
+    <<https://github.com/abarbu/matplotlib-haskell/raw/master/imgs/contour.png>>
+    .
+    > onscreen $ contourF (\a b -> sin (degreesRadians a) + cos (degreesRadians b)) (-100) 100 (-200) 200 10
 homepage:            https://github.com/abarbu/matplotlib-haskell
 license:             BSD3
 license-file:        LICENSE
diff --git a/test/Spec.hs b/test/Spec.hs
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -5,6 +5,7 @@
 import System.IO.Unsafe
 import Graphics.Matplotlib
 import System.IO.Temp
+import System.Random
 
 main = defaultMain tests
 
@@ -34,6 +35,7 @@
   , testPlot "quadratic" m10
   , testPlot "projections" m11
   , testPlot "line-options" m12
+  , testPlot "xcorr" mxcorr
   ]
 
 xs = [-0.54571992,  1.48409716, -0.57545561,  2.13058156, -0.75740497,
@@ -113,3 +115,11 @@
 m11 = projectionsF (\a b -> cos (degreesRadians a) + sin (degreesRadians b)) (-100) 100 (-200) 200 10
 
 m12 = plot [1,2,3,4,5,6] [1,3,2,5,2,4] @@ [o1 "'go-'", o2 "linewidth" "2"]
+
+datas = randoms (mkStdGen 42)
+
+datas lo hi = randomRs (lo,hi) (mkStdGen 42)
+
+mxcorr = 
+  where (xs :: Double) = take 100 datas
+        (ys :: Double) = take 100 datas