h,w = gets.chomp.split.map(&:to_i)
s = h.times.map{gets.chomp.chars}
_k =[-1,1]
0.upto(h-1) do |i|
  0.upto(w-1) do |j|
    if s[i][j] == '#'
      @ans = "No"
      _k.each do |k|
        if (0 <= i+k && i+k <= h-1 && 0 <= j+k && j+k <= w-1) &&
          s[i+k][j] == '#' || s[i][j+k] == '#'
          @ans = "Yes"
        end
      end
    end
  end
end
puts @ans
