The most effectively designed ballot for its purpose was probably the one used to decide the Anschluss referendum https://en.m.wikipedia.org/wiki/Austrian_A

The most effectively designed ballot for its purpose was probably the one used to decide the Anschluss referendum https://en.m.wikipedia.org/wiki/Austrian_Anschluss_referendum,_1938 https://en.m.wikipedia.org/wiki/Austrian_Anschluss_referendu...