Have you ever tried to model a braid?  I've been looking into how to do this and I found a couple of methods, but they involved manually setting point values for the spline - very nasty stuff and not easy to adjust.  I really wanted to do this using the Formula spline to do the heavy lifting.  Here's what I came up with.

First, consider the structure of a braid:
http://members.aol.com/StanDCmr/braid.html#Top

Linked from the above page by Stan Pope:

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