The preview render and model might look square and rigid, but in reality is quite easy-going and flexible.
Only in 3d printing! The final shape is a direct result of the geometric shifts which are possible. The final touch would be a small fabric inlay with a zipper for extra security.
Aug 31th : This model is giving me all sorts of trouble today: I'm unable to upload the final file due to an unknown error. I've been in contact with customer service; this is due to a known bug which should be resolved shortly.
Current model is below 500.000 polygons. For printing the original 2.000.000 polygon file would be best ;-)
In the mean time I am using the original upload-spot of my first test file. The main difference between them, is the handle and the scale.
Please judge by render and principle, not the model file ;-)