h,w = [int(i)  for i in input().split()]

listHW = []
flag = False
for i in range(0, h):
  listHW.append(list(input()))

  
for i in range(0, len(listHW)):
  if flag:
    break
  listw = listHW[i]
  #print("listw", listw)
  for ii in range(0, len(listw)):
    w = listw[ii]
    if w == "#":

      if i == 0:
        if ii == len(listw)-1:
          if w == listHW[i+1][ii]:
            w = "OK"
            break
        elif w == listw[ii + 1] or w == listHW[i+1][ii]:
          w = "OK"
          break
        elif ii == len(listw)-1:
          if w == listHW[i-1][ii] or w == listHW[i-1][ii]:
            w = "OK"
            break

      elif i == len(listHW)-1:
        if ii == len(listw)-1:
          if w == listHW[i-1][ii]:
            w = "OK"
            break
        elif w == listw[ii + 1] or w == listHW[i-1][ii]:
          w = "OK"
          break

      else:
        if ii == len(listw)-1:
          if w == listHW[i-1][ii] or w == listHW[i+1][ii]:
            w = "OK"
            break

        elif w == listw[ii + 1] or w == listHW[i-1][ii] or w == listHW[i+1][ii]:
          w = "OK"
          break
    else:
      continue

    flag = True

if flag:
  print("No")
else:
  print("Yes")
