I have a question: Does every party has to supply a seperate piece of paper and the voter then chooses which piece of paper to put into the ballot box? What do voters do with the non-chosen ballots, i.e. how is the secrecy of the vote protected?
The system I know from Germany is that there is one ballot per election and the voter puts a mark which party/candidate they choose with a pen on that.
Yes. Three actually, if you count the different elections. On the ballot is a list of names representing the party so you can vote for a particular candidate by marking the name.
Usually people pick a set of ballots for different parties to bring behind a screen where the choosen ballots are put in the envelope for the box. The non-choosen ones you can pocket to keep secret. Some people tend to leave them in the booth though.
The system I know from Germany is that there is one ballot per election and the voter puts a mark which party/candidate they choose with a pen on that.