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

res = True

for i in range(1, W-1):
    for j in range(1, H-1):
        if graph[i][j] == 1 and graph[i + 1][j] == 0 and graph[i - 1][j] == 0 and graph[i][j + 1] == 0 and graph[i][j - 1] == 0:
            res = False
print('Yes' if res else 'No')
