H, W = map(int, input().split())
graph = []
for _ in range(H):
    graph.append([0 if e == '.' else 1 for e in list(input())])

xx = [-1, 0, 1, 0]
yy = [0, -1, 0, 1]


res = True

for i in range(W):
    for j in range(H):
        if graph[i][j] == 1:
            flag = False
            for idx in range(4):
                nx, ny = i + xx[idx], j + yy[idx]
                if 0 <= x and x < W and 0 <= y and y < H and graph[nx][ny] == 1:
                    flag = True
            if not flag:
                res = False
                break
    if not res:
        break

print('Yes' if res else 'No')
