h, w = map(int, input().split())  # 入力

s = [0 for i in range(h)]
for i in range(h):
    s[i] = list(input())

print(s[0][0])
flag = False
for i in range(1, h-1):
    for j in range(1, w-1):
        if s[i][j] == '#':
            if s[i-1][j] == "#" or s[i+1][j] == "#" or s[i][j-1] == "#" or s[i][j+1] == "#":
                flag = True
            else:
                flag = False
        

if flag:
    print("Yes")
else:
    print("No")
