misc: add more scripts

misc/Sierpinski.lhs

@@ -0,0 +1,37 @@
+> import Diagrams.Backend.SVG.CmdLine
+
+> {-# LANGUAGE NoMonomorphismRestriction #-}
+> import Diagrams.Prelude
+
+#### Brent's Original Code
+> -- sierpinski 1 = triangle 1
+> -- sierpinski n =     s
+> --                  ===
+> --               (s ||| s) # centerX
+> --   where s = sierpinski (n-1)
+
+#### Code to change color at each level
+##### (Technically this is the complement of the Sierpinski triangle)
+> import Diagrams.Prelude
+> import Data.Colour.Palette.BrewerSet
+>
+> clrs :: [Colour Double]
+> clrs = brewerSet Purples 9
+>
+> sierpinski :: Int -> [Colour Double] -> Diagram B
+> sierpinski n c = go n <> triangle (2^n) # fc (clrs !! 0) # lw none
+>   where
+>     clrs = if null c then repeat black else cycle c
+>     go n
+>       | n == 1    = t1 # fc (clrs !! 1)
+>       | otherwise = appends tri (zip vecs (replicate 3 sierp))
+>       where
+>         tri   = scale (2 ^ (n-1)) $ t1 # fc (clrs !! (n+1))
+>         vecs  = [unitY, (rotateBy (-1/12) unitX), (rotateBy (1/12) unit_X)]
+>         sierp = go (n-1)
+>         t1    = triangle 1 # reflectY
+>
+> example =  sierpinski 7 clrs # lw none # center # frame 2
+
+
+> main = mainWith (example :: Diagram B)