I created this after seeing the contest open. A carrying case for a bicycle was the first thing that came to mind as I have not seen one on a bike here in the UK and I live on a very popular bike trail right outside my door. While it was fresh in my mind I decided to go ahead and create it.
It is a two part print job as I made it to work with a strap which many bicyclers use for one thing or another. I figured creating a hinge and clasp with a 3d printer would not be the strongest way to go.
I am sorry I cannot print test it as I do not have a printer big enough to print this size of an object...YET. But I created the files on Tinker Cad which is a great program for this kind of thing. The few things I have tried on Tinker Cad have printed real well. Enjoy.