h,w=map(int,input().split())
List=[input() for i in range(h)]
dx=[1,0,-1,0]
dy=[0,1,0,-1]

for i in range(h):
  for j in range(w):
    if List[i][j] == '.':
      continue
    else:
      c=0
      for k in range(4):
            i2 = i+dy[k]
            j2 = j+dx[k]
            if i2<0 or h<=i2:
                continue
            if j2<0 or w <=j2:
                continue
            else:
              if List[i2][j2]=="#":
                c+=1
if c == 0:
  print('No')
else:
  print('Yes')