H,W = (int(i) for i in input().split())

goal = []
for i in range(H):
    goal.append(input())

canComplete = True

for row in range(W):
    for column in range(H):
        above = row - 1
        bottom = row + 1
        left = column - 1
        right = column + 1
        
        if goal[row][column] == "#":
            if above >= 0 and goal[above][column] == "#":
                continue
            elif bottom < H and goal[bottom][column] == "#":
                continue
            elif left >= 0 and goal[row][left] == "#":
                continue
            elif right < W and goal[row][right] == "#":
                continue
            else:
                canComplete = False
                break

if canComplete:
    print("Yes")
else:
    print("No")