A braided river is not truly braided. Or at least it is impossible to identify any real braiding of strands in an image of the river because individual flows of water appear to intersect each other. Mathematically speaking, a braid is a type of knot. A knot is a continuous curve in space that does not intersect itself. So in a braid, individual strands pass over or under each other without intersecting.
example of a braid
Described by Adams in
The Knot Book, "A braid is a set of
n strings, all of which are attached to a horizontal bar at the top and bottom. Each string always heads downward as we move along any one of the strings from the top bar to the bottom bar. Another way to say the same thing is that each string intersects any horizontal plane between the two bars exactly once."
Given a specific number of strands, there is a specific
number of ways the strands can cross each other...
...and individual crossings can be combined
to form a more complex braid.
Braids can be 'multiplied' by stacking
them on top of one another.
Read the excerpt from The Knot Book (posted here on the blog) not necessarily to understand all the mathematics of knotting and braiding, but to help imagine different types of braids and how to manipulate them.
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