Population pyramids

Find a country example of each and describe the implications of each pattern.

Here's an amazing site from the US census.  This shows population pyramids by country (and projected populations).  Your assignment is to find four different patterns:
1.  expansive:  These pyramids have large bases and sharp points
2.  Constrictive:  Pyramids with smaller levels and larger size levels on top of them
3. Stationary:  Nearly rectangular (all levels except the top few are the same size)
4.  Asymetrical:   Too many or too few of one gender at various stages.