As noted in this already off the rec list diary at Kos, the use of old lever machines in NYC may have had something to do with the problem.  

Remember, Bushco sued NYC earlier this year to try to force them to comply with HAVA and, thereunder, adopt no-paper-trail digital/electronic machines, and NYC fought back noting all the deficiencies in those very mcahines. Because NYC has an election board evenly divided between the parties and a majority is required to move anything forward, not much ever gets done.  So, they never did get around to getting rid of the lever machines.  But, it turned out, they were smart (or lucky) because they probably have the least-hackable machines going. They're all analog - all mechanical.  No way to hack them.

In short the old lever machines, on the back, have many little window-type openings inside each of which is something which looks something like the odometer on a 1960-vintage car.  The lever machines are of that 1960s vintage so it was state of the art when built.  A series of wheels, driven by gears.  Each wheel would have a number from 0 to 9.  The voter would turn the lever for their respective candidate (to cast a vote) and then throw the big lever (to operate the curtain and record the vote), and then a series of mechanical linkages would operate to, ultimately, advance the numbers on that candidate's odometer by one.