Here's a link to an interesting TED-talk by biologist Diane Kelly on the anatomy and function of vertebrate penises:
At about 7 min into the talk she explains how a spiral structure is very flexible as it can be Extended and Bend versus a cross-layered structure which is more stiff and less flexible. This adds to the idea that the inner-structure should follow a spiralling flow ...
At about 7 min into the talk she explains how a spiral structure is very flexible as it can be Extended and Bend versus a cross-layered structure which is more stiff and less flexible. This adds to the idea that the inner-structure should follow a spiralling flow ...
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