H, W = map(int, input().split())
field = [list(input()) for i in range(H)]
flag = [[False] * H] * W
metaflag = []
dx = [1, 0, -1, 0]
dy = [0, 1, 0, -1]

for i in range(H):
    for j in range(W):
        if field[i][j] == '#':
            inflag = [False] * 4
            for k in range(4):
                ni = i + dx[k]
                nj = j + dy[k]
                if ni < 0 or ni >= H or nj < 0 or nj >= W:
                    inflag[k] = False
                elif field[ni][nj] == '#':
                    inflag[k] = True
            flag[i][j] = any(inflag)
        elif field[i][j] == '.':
            flag[i][j] = True
        metaflag.append(flag[i][j])

if all(metaflag):
    print('Yes')
else:
    print('No')
