Hmm. I just tested it in Excel. “No fill” will make it transparent. White would cover the grid lines.
So, I guess it’s doable using a set of columns with identical colours. Calculating the values from a picture would also be possible - for a mad man.
Perhaps it should be decided by a cognitive test instead of age. This is a dangerous road though, because a lot of people with cognitive disabilities can and should be allowed to vote for themselves.
Maybe the test could be made to test if a person understands what an election is and them being able to form their own opinion.
The main issue isn’t age, but rather that a lot of people vote for something that they think others expect them to vote for without ever forming an opinion of their own.
However those people should also be allowed to represent themselves, so I think all elections ought to have the option of voting for “shit, I don’t know, I have no idea what’s this is about”, and if that vote came over a certain threshold, then the election should be void and postponed for a week.