h, w = map(int, input().split())
board = []
for i in range(h):
  board += [input()]

result = True

def check(i, j):
  if board[i][j] == '.':
    return True
  
  if i == 0:
    if j == 0:
      if board[i][j + 1] == '.' and board[i + 1][j] == '.':
        return False
    elif j == w - 1:
      if board[i][j - 1] == ',' and board[i + 1][j] == '.':
        return False
    else:
      if board[i][j - 1] == ',' and board[i][j + 1] == '.' and board[i + 1][j] == '.':
        return False
  elif i == h - 1:
    if j == 0:
      if board[i][j + 1] == '.' and board[i - 1][j] == '.':
        return False
    elif j == w - 1:
      if board[i][j - 1] == ',' and board[i - 1][j] == '.':
        return False
    else:
      if board[i][j - 1] == ',' and board[i][j + 1] == '.' and board[i - 1][j] == '.':
        return False
  else:
    if j == 0:
      if board[i][j + 1] == '.' and board[i - 1][j] == '.' and board[i + 1][j] == '.':
        return False
    elif j == w - 1:
      if board[i][j - 1] == ',' and board[i - 1][j] == '.' and board[i + 1][j] == '.':
        return False
    else:
      if board[i][j - 1] == ',' and board[i][j + 1] == '.' and board[i - 1][j] == '.' and board[i + 1][j] == '.':
        return False

  return True

for i in range(h):
  for j in range(w):
    result = check(i, j)
    if not result:
      break
  if not result:
    break

if result:
  print("Yes")
else:
  print("No")
  
