def repaint(h, w):
    s = [['.']*(w+2)]+[list('.'+input()+'.') for i in range(h)]+[['.']*(w+2)]
    for i in (1, h+1):
        for p in (1, w+1):
            if s[i][p] == '#':
                if s[i-1][p] == s[i][p+1] == s[i+1][p] == s[i][p-1] == '.':
                    return 'No'
    return 'Yes'
H, W = map(int, input().split())
print(repaint(H, W))