Been fooling around here with braids. Em got a kit for her birthday recently (she's ten now!) to make friendship bracelets. I thought I'd seen them somewhere before and googled Japanese braiding. Lo and behold there is a braiding technique called Kumihimo (which means plaiting string).
Here is an example of a flat braid made with the square foam loom. There is one main kind of loom for the rounded braids (called a Marudai--it is made of wood traditionally), A loom for large intricate flat braids is called a Takadai. It is a related technique but with a woven aspect.
Here is one of the patterns for a rounded braid, a kind of flower or dot. The pattern is marked out on one of Em's looms. The kit that Em got came with 4 dense foam looms (2 round, 2 square). The kit is from ALEX and included embroidery floss and beads (which can be added to some of the braids).
The ALEX kit is an easy entry to the world of Kumihimo and my girls and I have enjoyed it tremendously. We are waiting to borrow a book by Roderick Owen "Braids: 250 from Japan, Peru and Beyond". A couple other books we have from the library don't talk about using the foam boards at all but concentrate on the Japanese traditional Marudai or Takadai. The traditional patterns for the Marudai can work on the foam boards as well. There are other foam boards available called Kumilooms which can come with bobbins to help with long threads (which are easily tangled while working the braid) and also two from Beadsmith (many people make elegant necklaces from silk string).