x = list(map(int,input().split()))
h = x[0]
w = x[1]
can = list()
for i in range(h):
    y = input()
    can.append(y)
z = 0
for i in range(h):
    for j in range(w):
        if can[i][j] == "#":
            if i > 0:
                if can[i - 1][j] == "#":
                    break
            if i < h - 1:
                if can[i + 1][j] == "#":
                    break
            if j > 0:
                if can[i][j - 1] == "#":
                    break
            if j < w - 1:
                if can[i][j + 1] == "#":
                    break
            z += 1
            print(i)
            print(j)
if z == 0:
    print("Yes")
else:
    print("No")