h,w=map(int,input().split())
list1=[[0 for i in range(w)]for j in range(h)]
list2=[[0 for i in range(w)]for j in range(h)]
dx=[-1,-1,0,0]
dy=[0,0,-1,1]
a=0
for j in range(h):
 s=input()
 for i in range(w):
  list1[j][i]=s[i]
for j in range(h):
  for i in range(w):
   if list1[j][i]=="#":
    for k in range(4):
     xk=i+dx[k]
     yk=j+dy[k]
     if xk>=0 and xk<w and yk>=0 and yk<h:
      list2[yk][xk]+=1
for j in range(h):
  for i in range(w):
    if list1[j][i]=="#" and list2[j][i]==0:
     None
    else:
     a+=1
if a==h*w:
 print("Yes")
else:
 print("No")
