This instance was designed by me for the IPhone 5s/5c using Solidworks.
I found the ring-shaped layout gave an intriguing appearance to the instance, in addition to resembling a snowflake as a Christmas layout. I did not that the design on its own seemed as great, so I duplicated it putting them at different points along the case as I was designing it. This worked out nicely adding more details over the rear of the case.
The case cuts easily onto the telephone shielding the edge and the rear from scrapes!
I designed it to be a quick and simple print - set level down onto the print bed, (so the file will print as it is - without any need for support materials or any additional measures).
The case was printed using an Ultimaker 2.
I used white PLA - at a layer height of 0.2mm and print speed 50mm/s with great effects, as it's a quick print you could reduce the layer height farther or select slower print settings to create an instance of even higher quality!