H, W = map(int, input().split())
S = [['.' for _ in range(W+2)]]+[['.'] + list(input())+ ['.'] for _ in range(H)]+[['.' for _ in range(W+2)]]
Flag = True
for i in range(1,H+1):
    for j in range(1, W+1):
        if S[i][j]=='.':
            continue
        if S[i-1][j-1] == S[i-1][j+1] == S[i+1][j-1] == S[i+1][j+1] == '.':
            Flagb = False
            break
    else:
        continue
    break
if Flag:
    print('Yes')
else:
    print('No')