{-# LANGUAGE FlexibleInstances #-}

import Data.List ( transpose, group )

import Control.Monad ( replicateM )

-- StdIn

class In a where stdin :: IO a
instance In Int where stdin = read <$> getLine
instance In [Int] where stdin = map read . words <$> getLine
instance In String where stdin = getLine
instance In [String] where stdin = words <$> getLine

class In' a where stdinN :: Int -> IO a
instance In' [Int] where stdinN n = replicateM n $ read <$> getLine
instance In' [[Int]] where stdinN n = replicateM n $ map read . words <$> getLine
instance In' [String] where stdinN n = replicateM n getLine
instance In' [[String]] where stdinN n = replicateM n $ words <$> getLine

main :: IO ()
main = do
  [h, _] <- stdin
  css <- stdinN h
  let ss = css ++ transpose css
  putStrLn $ case any (any (\cs -> length cs > 1 && '#' `elem` cs) . group) ss of
    True -> "Yes"
    False -> "No"

