import Control.Monad
main=do
 [h,w]<-map read.words<$>getLine
 s<-replicateM h getLine
 putStrLn(f 0 0 h w s)
  where f i j h w s |i==h ="Yes"
                    |j==w = f (i+1) 0 h w s
                    |otherwise =if(g i j h w s)then"No"else(f i (j+1) h w s)
        g i j h w s =((s!!i)!!j=='#')&&
                     (if j==0 then True else(s!!i)!!(j-1)=='.')&&
                     (if j==(w-1) then True else(s!!i)!!(j+1)=='.')&&
                     (if i==0 then True else(s!!(i-1))!!j=='.')&&
                     (if i==(h-1) then True else(s!!(i+1))!!j=='.')