module Main where

import Control.Applicative
import Control.Monad
import Data.Array

check :: Array (Int, Int) Char -> (Int, Int) -> Bool
check a (i, j)
    | a ! (i, j) == '.' = True
    | otherwise         = any (\w -> a ! w == '#') ws
  where
    bs = bounds a
    ws = filter (inRange bs) [(i-1, j), (i+1, j), (i, j-1), (i, j+1)]

main :: IO ()
main = do
    [h, w] <- fmap read . words <$> getLine
    ss <- concat <$> replicateM h getLine
    let ary = listArray ((1, 1), (h, w)) ss
    let ans = all (check ary) (indices ary)
    if ans
        then putStrLn "Yes"
        else putStrLn "No"