H,W = map(int,input().split())
grid = [[]] * H

for i in range(H):
  c = list(input())
  grid[i] = c
  
black = "#"
white = "."

ans = "Yes"


for i in range(H):
  for j in range(W):
    if grid[i][j] == black:
      here = grid[i][j]
      around = ""
      
      if i == 0:
        around += grid[i + 1][j]
      elif i == W - 1:
        around += grid[i - 1][j]
      else:
        around += (grid[i - 1][j] + grid[i + 1][j])
      
      if j == 0:
        around += grid[i][j + 1]
      elif j == H - 1:
        around += grid[i][j - 1]
      else:
        around += (grid[i][j + 1] + grid[i][j - 1])
      
      if all([i == white for i in around]):
        ans = "No"
        break

print(ans)
