h, w = list(map(int, input().split()))
s = [input() for j in range(h)]
op = [(-1, 0), (0, -1), (0, 1), (1, 1)]
for i in range(h):
  for j in range(w):
    if s[i][j] == '.':
      continue
    count = 0
    for k in range(4):
      x = i + op[k][0]
      y = j + op[k][1]
      if x < 0 or y < 0 or x >= h or y >= w:
        continue
      if s[x][y] == '.':
        count += 1
    if count == 4:
      print('No')
      exit()
      
print('Yes')