imports sys

def sub(field, x, y):
  if y < 0 or x < 0 or y >= len(field) or x >= len(field[y]):
    return True
  if field[y][x] != '#':
    return False
  return True

def isok(field, x, y):
  units = [(0, 1), (1, 0), (0, -1), (-1, 0)]
  for unit in units:
    _x = x + unit[0]
    _y = y + unit[1]
    if not sub(field, _x, _y):
      return False
  return True
    
l = sys.stdin.readline()
xy = [int(x) for x in l.rstrip('¥n').split(' ')]
height = xy[0]
width = xy[1]

field = []
for _ in xrange(height):
  field.append(sys.stdin.readline())
 
for y in len(field):
  for x in len(field[y]):
    if not isok(field, x, y):
      print 'No'
print 'Yes'
