On today’s pages, Zevachim 21 and 22, we learn that the priests in the ancient Temple invented a noisy contraption for no other reason than letting their colleagues know it was time to begin getting ready for work. In doing so, it turns out, they figured out a massively important part of modern product design, namely making sure that our gadgets make the right sounds and prepare us for the task ahead. Why do vacuum cleaner makers make their vacuum cleaners much louder on purpose? And why is your car lying to you by pumping fake sounds through your car speakers? Listen and find out.