H,W = map(int,input().split())
s = [list(map(int,input().split())) for _ in range(H)]

for h in range(H):
    for w in range(W):
        if s[h][w] == "#":
            if h>0 ans s[h-1][w]=="#":
                continue
            elif h<H-1 ans s[h+1][w]=="#":
                continue
            elif w>0 ans s[h][w-1]=="#":
                continue
            elif h<W-1 ans s[h][w+1]=="#":
                continue
            else:
                print("No")
                break
else:
    print("Yes")