diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
diff --git a/Randsolid.hs b/Randsolid.hs
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+++ b/Randsolid.hs
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+-- Change the root window background to a random solid colour.
+
+import System.Random
+import Control.Applicative
+import Data.Bits
+import Graphics.X11.Xlib.Window
+import Graphics.X11.Xlib.Display
+import Graphics.X11.Xlib.Types
+
+
+-- These are the bounds on the random generation of values.
+data Values = V
+	{ sat :: (Double, Double) -- ^ Saturation, valid values in [0..1]
+	, hue :: (Double, Double) -- ^ Hue, valid values in [0..365]
+	, val :: (Double, Double) -- ^ Value, valid values in [0..1]
+	}
+
+-- Default bounds.
+defaultValues = V
+	{ sat = (0.12, 0.30)
+	, hue = (0, 365)
+	, val = (0.5, 0.7)
+	}
+
+
+data HSV = HSV Double Double Double deriving Read
+instance Show HSV where show = hsv2hex
+
+data RGB = RGB Double Double Double
+instance Show RGB where show = rgb2hex
+
+-- Convert a HSV colour to its hexadecimal representation.
+hsv2hex :: HSV -> String
+hsv2hex = rgb2hex . hsv2rgb
+
+-- Convert a RGB colour value into its hexadecimal representation.
+rgb2hex :: RGB -> String
+rgb2hex (RGB r g b) = "#" ++ r' ++ g' ++ b'
+	where
+		r' = table !! (floor (r * 255))
+		g' = table !! (floor (g * 255))
+		b' = table !! (floor (b * 255))
+		table = [ x:y:[] | x <- "0123456789abcdef", y <- "0123456789abcdef" ]
+
+
+hsv2rgb :: HSV -> RGB
+hsv2rgb (HSV h s v) = case h' of
+	0 -> RGB v t p
+	1 -> RGB q v p
+	2 -> RGB p v t
+	3 -> RGB p q v
+	4 -> RGB t p v
+	_ -> RGB v p q
+	where
+		p = v * (1 - s)
+		q = v * (1 - f * s)
+		t = v * (1 - (1 - f) * s)
+
+		f = (h / 60) - (fromIntegral (floor (h / 60)))
+		h' = floor (h / 60) `mod` 6
+
+
+hsv2pixel :: HSV -> Pixel
+hsv2pixel hsv = sum $ map (\(pos, val) -> shiftL (floor (255 * val)) (8 * fromIntegral pos)) bits
+	where
+		(RGB r g b) = hsv2rgb hsv
+		bits = zip [0,1,2] [b,g,r]
+
+
+randcolour :: Values -> IO HSV
+randcolour v = do
+	h <- randomRIO (fst $ hue v, snd $ hue v)
+	s <- randomRIO (fst $ sat v, snd $ sat v)
+	v <- randomRIO (fst $ val v, snd $ val v)
+	return $ HSV h s v
+
+
+randsolid :: Values -> IO ()
+randsolid v = do
+	dpy  <- openDisplay ""
+	root <- rootWindow dpy $ defaultScreen dpy
+	setWindowBackground dpy root . hsv2pixel =<< randcolour v
+	clearWindow dpy root
+	closeDisplay dpy
+
+
+main = randsolid defaultValues
diff --git a/Setup.lhs b/Setup.lhs
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--- /dev/null
+++ b/Setup.lhs
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+#!/usr/bin/env runhaskell
+> import Distribution.Simple
+> main = defaultMain
diff --git a/randsolid.cabal b/randsolid.cabal
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--- /dev/null
+++ b/randsolid.cabal
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+Name:                randsolid
+Version:             0.1
+Synopsis:            Set the background of your root window to a random colour.
+Description:         Set the background of your root window to a random colour.
+Category:            System
+License:             PublicDomain
+License-file:        LICENSE
+Author:              Johannes Martinsson
+Maintainer:          w@antiklimax.se
+Cabal-version:       >= 1.2
+Build-type:          Simple
+
+Executable           randsolid
+    Main-is:         Randsolid.hs
+    Build-depends:   base >= 3 && < 4, X11, random