In 1881, Anthony Beranek of Chicago patented the first voting machine appropriate for use in a general election in the United States. Beranek's machine presented an array of push buttons to the voter, with one row per office on the ballot, and one column per party. Interlocks behind each row prevented voting for more than one candidate per race, and an interlock with the door of the voting booth reset the machine for the next voter as each voter left the booth.