def main():
  t = input().split(" ")
  H, W = int(t[0]), int(t[1])
  
  s = ["."*(W+2)]
  for i in range(H):
    t = input().strip()
    s.append("".join(['.', t, '.']))
  s.append("."*(W+2))
  flag = True
  for i in range(H):
    for j in range(W):
      if s[i+1][j+1] == '#':
        if s[i][j+1]=='.' and s[i+2][j+1]=='.' and s[i+1][j]=='.' and s[i+1][j+2]=='.':
          flag == False
  if flag:
    print("Yes")
  else:
    print("No")
main()
