Optical scan machines are devices used to read and tally votes on paper ballots. Voters fill out their choices on the ballot, which is then fed into the machine. The machine uses light sensors to detect marks made by the voter, converting them into digital data for counting. These machines are commonly used in elections to ensure accuracy and efficiency. They can quickly process large volumes of ballots, making them a popular choice for election officials. Optical scan machines help maintain the integrity of the voting process by providing a reliable method for counting votes.