h,w = map(int,input().split())
table = [0]*h
for i in range(h):
    table[i] = list(input())

for i in range(h):
    for j in range(w):
        if table[i][j] == "#":
            if i - 1 >= 0 and table[i-1][j] == "#":
                ok = True
            elif i + 1 <= h-1 and table[i+1][j] == "#":
                ok = True
            elif j - 1 >= 0 and table[i][j-1] == "#":
                ok = True
            elif j + 1 <= w-1 and table[i][j+1] == "#":
                ok = True
            else:
                ok = False
            if ok == False:
                 print("NO")
                 exit()
print("YES")