h,w=gets.split.map(&:to_i)
field=readlines
field << '.' * w

p field
p field[1][1]

0.upto(h-1) do |i|
  0.upto(w-1) do |j|
    next if field[j][i] == '.'
    ok = [
      field[j-1][i],
      field[j+1][i],
      field[j][i-1],
      field[j][i+1],
    ].any? {|b| b == '#'}

    unless ok
      puts 'No'
      exit 0
    end

  end
end

puts 'Yes'