String quilts are lots of fun!
For variation, consider using the same color fabric for the first strip of each block (the diagonal strip/string you start in the center with). That will give you some uniformity, and will also give you a diamond shape when the blocks are sewn together.
Another option is to start w/ a rectangular foundation rather than a square one. Your strings will then form a diamond shape.
If you look in webshots, you should be able to find lots of examples. A warning: They can be addictive!