You will commonly find the following outlets:
This is the new model of the old outlet
The outlet at the right is currently the most common is Brazilian households. you can still use the old powercords, but more common is the powerplug as shown in the picture
This is the standard outlet with grounding
The picture at the left shows the standard outlet to be used in kitchens, living rooms etc. Almost all appliances sold today comes with a powercord with three poles. You can put the powercords with two poles (See above) as well in this outlet.
This is the EU (Not the Brazilian!!) standard power cord. You can use it in both of the above outlets, without any problem.
Standard Brazilian powercord with two and three pins
And here you have the original Brazilian two and three pole powerplugs. Of course they work.
Powercord for complicated country
What will not work:
The powerplug at the right is being used in Switzerland. It looks extremely similar to the Brazilian three pole powerplug, but it simply will not fit. What you could do is to get rid of the middle pole and then it works.
EU Powercord three pin
Also this plug will not fit in the Brazilian outlets. In the older (not shown on this page) you could push them in the outlet, however once you tried to pull it you most likely broke the whole outlet.
