H, W = map(int, input().split())
a = []
for i in range(H):
  temp = list(input())
  a.append(temp)
for i in range(H):
  for j in range(W):
    if a[i][j] == '.':
      continue
    if i == 0 and j == 0:
      if a[i][j+1] == '.' and a[i+1][j] == '.':
        print('No')
        exit()
    elif i == 0 and j == W-1:
      if a[i][j-1] == '.' and a[i+1][j] == '.':
        print('No')
        exit()
    elif i == 0:
      if a[i][j-1] == '.' and a[i][j+1] == '.' and a[i+1][j] == '.':
        print('No')
        exit()
    if i == H-1 and j == 0:
      if a[i][j+1] == '.' and a[i-1][j] == '.':
        print('No')
        exit()
    elif i == H-1 and j == W-1:
      if a[i][j-1] == '.' and a[i-1][j] == '.':
        print('No')
        exit()
    elif i == H-1:
      if a[i][j-1] == '.' and a[i][j+1] == '.' and a[i-1][j] == '.':
        print('No')
        exit()
    if j == 0:
      if a[i+1][j] == '.' and a[i-1][j] == '.' and a[i][j+1] == '.':
        print('No')
        exit()
    if j == W-1:
      if a[i+1][j] == '.' and a[i-1][j] == '.' and a[i][j-1] == '.':
        print('No')
        exit()
print('Yes')