gol.hs

import System.Random

randomCells :: Int -> StdGen -> [Int]
randomCells size gen = take size $ randomRs (0, 1) gen

createGeneration :: [Int] -> Int -> [[Int]] -> [[Int]]
createGeneration [] _ generation = generation -- use _ when you don't use a variable
createGeneration cells width generation =
    let line = take width cells
     in createGeneration (drop width cells) width (line:generation)

main :: IO() -- declare type signature
main =
    let cells = randomCells 12 (mkStdGen 123)
     in print (createGeneration cells 4 [])