H, W = map(int, input().split())
s = [input() for i in range(H)]

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