H,W=map(int, input().split())
s = []
dx = [ -1, -1, 1, 1]
dy = [ -1, 1, -1, 1]
ans = "Yes"
for i in range(H):
  s.append( input())
for y in range(H):
  for x in range(W):
    if s[y][x] == '#':
      ng = 1
      for i in range(4):
        nx = x + dx[i]
        ny = y + dy[i]
        if (ny < 0) or (ny >= H) or (nx<0) or (nx>=W):
          continue
        if s[ny][nx] == '#':
          ng = 0
      if ng == 1:
        ans = "No"
print(ans)
        

  
    
