import sys
h,w=map(int,input().split())
s=[]
for num in range(h):
  s.append(list(map(int,input().split())))
if w==1:
  if h==1:
    if s[0][0]=='#':
      print('No')
      sys.exit()
  if h==2:
    if (s[0][0]=='#' and s[1][0]=='.') or (s[0][0]=='.' and s[1][0]=='#'):
      print('No')
      sys.exit()  
  else:
    for i in range(h-2):
      if (s[i][0]=='.' and s[i+1][0]=='#' and s[i+2][0]=='.'):
        print('No')
        sys.exit()
if w==2:
  if h==1:
    if (s[0][0]=='.' and s[0][1]=='#') or (s[0][0]=='#' and s[0][1]=='.'):
      print('No')
      sys.exit()  
  else:
    for i in range(h-1):
      if s[i][0]=='.' and s[i][1]=='#':
        if s[i+1][1]=='.':
          print('No')
          sys.exit()
      if s[i][0]=='#' and s[i][1]=='.':
        if s[i+1][0]=='.':
          print('No')
          sys.exit()     
for i in range(h):
  for j in range(w-2):
    if s[i][j]=='.' and s[i][j+1]=='#' and s[i][j+2]=='.':
      if s[i][j+1]=='.':
        print('No')
        sys.exit()
    if s[i][0]=='#' and s[i][1]=='.':
      if s[min(h-1,i+1)][0]=='.':
        print('No')
        sys.exit()
    if s[i][w-2]=='.' and s[i][w-1]=='#':
      if s[min(h-1,i+1)][w-1]=='.':
        print('No')
        sys.exit()
print('Yes')
  
