
H, W = map(int, input().split())
s = [0]*H

def check(x, y):
    return 0 <= x and x < W and 0 <= y and y < H

def test(x, y):
    if check(x, y):
        return s[y][x]
    else:
        return "."

for i in range(H):
    s[i] = input()
ans = "Yes"
for y in range(H):
    for x in range(W):
        l = list(map(lambda p: test(p[0], p[1]), [(x-1, y),(x+1, y),(x, y-1),(x, y+1)]))
        if "#" not in l:
           ans = "No"
           break
print(ans)

