import sys
h,w=map(int,input().split())
s=[]
for i in range(h):
  s.append(list(map(int,input().split())))
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')
  