h,w=map(int,input().split())
a=[0]*h+2
a[0]='.'*(w+2)
a[h+1]=a[0]
for _ in range(1,h+1):
  a[_]='.'+input()+'.'
x='Yes'
for i in range(1,h+1):
  for j in range(1,w+1):
    if a[i][j]=='#':
      if a[i-1][j]=='.' and a[i+1][j]=='.' and a[i][j-1]=='.' and a[i][j+1]=='.':
        x='No'
print(x)