h, w = map(int, input().split())
pic = []
pic.append(["."] * (w + 2))
for i in range(h):
  pic.append(["."] + list(input()) + ["."])
pic.append(["."] * (w + 2))
print(pic)

can_paint = True
for i in range(1, h+1):
  for j in range(1, w+1):
    if pic[i][j] == "#":
      up = pic[i-1][j]
      down = pic[i+1][j]
      left = pic[i][j-1]
      right = pic[i][j+1]
      if up == "." and down == "." and left == "." and right == ".":
        can_paint = False
      
if can_paint == True:
  print("Yes")
else:
  print("No")