Brazil uses two sets of coins now.

One set was designed in 1994 (after the introduction of the Real) and is an splendid example of coin usability done wrong. 5, 10 and 50 centavos coins not only have identical design and color (all made of stainless steel), but they are also identical in size.

This problem was noticed by 1998 and a new set of coins was designed. This time the 5 centavos coin is red copper, 10 and 25 are made from yellow brass but differ in size dramatically, 50 is all nickel and R$1 is bimetalic. They also very in size significantly, as well as in thickness. So, you can’t mistake R$1 for smaller denominations because it’s much bigger, and you can’t mistake 50 centavos coin because it is much thicker. And they look nice. Altogether, it really is a job well done.

It wouldn’t be Brazil, though, if there wasn’t a catch. The 1994 coins were kept in circulation! I am not quite sure why – presumably it was decided that replacing them would be too costly. The bottom line is that there are now two coins of each denomination and picking the one you want is quite difficult. I think I've read that a typical coin has a life expectancy of about 25 years, so this madness will continue for a while.

(If you want to see more professional pictures of the two sets of coints, Banco Central do Brasil has both Set 1 and Set 2.)