import Data.List

main = do
  getLine
  co <- getContents
  let css = lines co
  let ans = compute css
  putStrLn $ if ans then "Yes" else "No"

-- 全ての'#'について、上下左右のいずれかに'#'があればよい。
-- 端については '.' にして失敗させる

compute :: [String] -> Bool
compute css = and $ map and chkSs
  where
    chk '.' _   = True
    chk '#' '#' = True
    chk _   _   = False
    cssN = repeat '.' : css -- 上
    cssS = tail css ++ [repeat '.'] -- 下
    cssE = map (tail.(++ ".")) css -- 右
    cssW = map ('.' :) css -- 左
    chkNs = zipWith (zipWith chk) css cssN
    chkSs = zipWith (zipWith chk) css cssS
    chkEs = zipWith (zipWith chk) css cssE
    chkWs = zipWith (zipWith chk) css cssW
    chkNSs = zipWith (zipWith (||)) chkNs chkSs
    chkEWs = zipWith (zipWith (||)) chkEs chkWs
    chk4s = zipWith (zipWith (||)) chkNSs chkEWs
