Peasants are required for this hint. When you go to a building, click it and pause the game. Click the "Halt Production" button and then press it again. Unpause the game. The "No Workers" symbol will appear above the building, but the old workers will still be working there, and new ones will come there too. Thus, more than one person outputting resources at that building, making it so that you could make things such as 1 woodcutter that inputs the same amount of resources as 5 of them.