def calc(x, y):
    x2 = x
    y2 = y - 1
    x4 = x - 1
    y4 = y
    x5 = x + 1
    y5 = y
    x7 = x
    y7 = y + 1
    return x2, y2, x4, y4, x5, y5, x7, y7

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

for i in range(h * w):
    x = i // h
    y = i % h
    c = 0
    if s[x][y] == "#":
        x2, y2, x4, y4, x5, y5, x7, y7 = calc(x, y)
        aaa = [[x2, y2], [x4, y4], [x5, y5], [x7, y7]]
        for (xx, yy) in aaa:
            if ((xx >= 0) & (xx < h) & (yy >= 0) & (yy < w)):
                if s[xx][yy] == "#":
                    c += 1
        if c == 0:
            ans = "No"
            break
        else:
            ans = "Yes"
print(ans)