h,w =map(int,input().split())
s = [input() for i in range(h)]
dx = [ 1, 1,-1,-1]
dy = [ 1,-1, 1,-1]
for i in range(h):
    for j in range(w):
        if s[i][j]=="#":
            count = 0
            for k in range(4):
                x = i + dx[k]
                y = j + dy[k]
                if s[x][y] == "#" and x >= 0 and x <= h-1 and y >= 0 and y <= w-1:
                    count += 1
            if count == 0:
                print("No")
                break
        else:
            continue
        break
    else:
        continue
    break
print("Yes")
            
                
            