What is the differance between Quartersawn vs. Plainsawn?

Plainsawn wood is the type most typicaly seen today. When the log is cut in to planks all the cuts are parallel to each other. See the pictures below for illustration.

 

With Quartersawn wood the log is first quartered (hence quartersawn) and then diagonaly from the center. This results in a grain that is more vertical when looking at the plank end on. See the pictures below for an illustration..