Where does the shape of pretzels come from? I wonder where the shape of pretzels originated.

My guesses:


The holes make it easy to put them on a stick or rope and store them in a place (under the roof?) where mice would not get it. 
Originally the pretzel was a long thin stick, but it was impractical to transport. The pretzel shape provided stability to carry it around. It could be broken into smaller stick-like pieces and eaten.
It resembles some symbol.
Just for fun, because the kids liked it.
According to the Wikipedia article, the following is a likely story (or something similar to it, anyway) but may not be exactly right:

The very beginning of this youtube video of Alton Brown's Good Eats explains it rather well:

http://www.youtube.com/watch?v=CZR_evWiDbY

Essentially, it was created by a monk as a reward for children who did their daily prayers.  The shape looks somewhat like a person folding their arms across their chest, which is an older way to pray.

There is also the possibility that the loops make it practical to hang on sticks, more for display than for keeping the food safe.

http://en.wikipedia.org/wiki/Pretzel