Listening to the news recently, they were discussing the advanced electronic voting system being used in the Brazilian election.
Instead of casting votes on paper where the user might accidentally tick the wrong box, and accidentally select a candidate that they didn’t want to they introduced a system where the user chooses 13 for one candidate and 45 for another.
Because each candidate used completely different numbers, instead of for example 13 and 14, there was no chance of a user accidentally pressing the wrong number and voting for the wrong person.
The user could of course enter in a wrong number for example 46 which would spoil the vote.
I can only assume there would be mechanisms in place to inform the user that they have made an incorrect entry if they hadn’t entered 13 or 45 so that they would get the opportunity to retry, and their vote could still be counted. Or may not… as I read during the Scottish election that there was what seemed to me a fairly large number of spoilt votes including examples where people didn’t make a selection, and left the paper blank.
The system would fall over quite quickly if there were more that 5 candidate because a number would have to be pressed more than once. But for now, it seems to be perfectly adequate for the job.