Âm thanh chia sẻ

Back in the day, soldiers had a pretty clever way to send messages between towers. So picture this: a soldier lights up a torch on top of his tower. That flame is basically a signal to the next tower over. Now here’s the cool part—each tower has this tall water bucket with the same set of instruct…

Back in the day, soldiers had a pretty clever way to send messages between towers. So picture this: a soldier lights up a torch on top of his tower. That flame is basically a signal to the next tower over. Now here’s the cool part—each tower has this tall water bucket with the same set of instructions carved on it. The moment the other tower spots the torch, both towers start draining water from their buckets at the exact same time. As the water level drops, it lines