def solve():
    for i in range(1, W):
        for j in range(1, H):
            if s[i][j] == "#":
                if s[i + 1][j] == "." and s[i][j + 1] == "." and s[i-1][j] == "." and s[i][j-1] == ".":
                    print("No")
                    return;
    else:
        print("Yes")


H, W = [int(i) for i in input().split()]
s = [["."] * (W + 2)]
for _ in range(H):
    sh = ["."] + list(input()) + ["."]
    s.append(sh)
s.append([["."] * (W + 2)])
solve()



