h,w = map(int, input().split())
l = [None]*h
for i in range(h):
    l[i] = list(input())

dx = [1, 0, -1, 0]
dy = [0, 1, 0, -1]

for i in range(h):
    for j in range(w):
        if l[i][j] == "#":
            ok=False
            for k in range(4):
                nx = j + dx[k]
                ny = i + dy[k]
                if 0<=nx<w and 0<=ny<h and l[ny][nx]=="#":
                    ok=True
            if not ok:
                print(i,j)
                print("No")
                exit()
print("Yes")