The Western Confucian: Cob Houses:
You've seen them in Korea, whether or not you knew what they were (and I did not); The New Beginning has links galore about them overseas — The Barclays Self Build Cob House, More on cob, and More on cob houses.
And you've seen them in South Africa, whether or not you knew what they were:
What is Cob?:
A cob house is made of clay, sand and straw. The mixture is 'kneaded' like dough before it is put into place by stomping on it with your feet or using a cement mixer for larger scale operations. The clay acts as the glue, while the sand gives strength to the mixture and the straw gives the walls tensile strength once hardened into place. Because cob is very flexible to work with, the builder is free to create just about any shape, so you won't find too many cob homes that look similar to each other.