The today's flag is from Rio de Janeiro state (don't confuse with Rio de Janeiro city, nicknamed by tourist as "Rio"). The flag is this:
It's not a bad coat of arms, I have to admit, but it's against the "simplify" commandment. Other question is that, when the state flag and arms were created, the Rio city was the Federal District, so it's more likely a Rio de Janeiro "countryside" flag. My fist proposal was something like simplification of it:
Sorry the lack of symmetry, a new eagle image would improve it. The scarlet is from Rio de Janeiro city flag. I don't know exactly why I put the star in green, but it's good this way. The quartered blue and white is a must, not just because it's a good basis to the flag, but too because it was used in state flag since 1889, at least, but a previous version was used in Empire times.The seal from coat of arms has no meaning known by me, and I couldn't find any early use (it's a strange case of "seal on arms"), but it's a good element.
My two next proposal are more ambitious. These are the results:
Nº 1: Sea blue in sky blue.
Nº 2: Sky blue in sea blue.
Any of them would be a great flag, though. The first proposal is more traditional, but maybe the second would be better in sunlight. That's all!
What do you feel about my proposals? Comment.
With this, I count 24 Brazilian state flag. Now, it's lasting only three.