1: A bunch of people (from both parties and nominally anyone else who feels like showing up) look at the ballot box to confirm that it's a empty cardboard (or w

1: A bunch of people (from both parties and nominally anyone else who feels like showing up) look at the ballot box to confirm that it's a empty cardboard (or whatever) box with no interesting properties. (This part is what's impossible with a voting machine, for obvious reasons.) 2: People watch the box to make sure it's not tampered with as people put their ballots in. (This works to a point with voting machines, although a attacker interacts with a voting machine for much longer than the ~6 sec it takes to drop a paper ballot in a box.) 3: The ballots are taken out and counted, with more watching. Due to physical laws like conservation of mass, it's very hard to make the number of ballots coming out differ from the number that went in, and even changing existing ballots is nontrivial. (Voting machines can silently delete, alter, or add ballots matching arbitrary criteria.)