This thing was made with Tinkercad.
If you have a Generation III Prius (2010-present), you can pop off the UGLY wheel covers to release the alloy beasts underneath. Except - you'll have a hole in the center of the wheel that begs for a decorative cap. This is precisely measured from the Toyota part number 42603-52110 (pictured).
This has a stylized lightning bolt embossed in the top of the wheel cover.
Also fits Yaris, Vios
These and other center cap designs are available through Shapeways:
This work is licensed under the Creative Commons - Attribution - Non-Commercial license. This license applies only to the files and documents available for download from the Thing Files section of this Thing.
All other related content (photographs, videos, and verbiage such as contained in "Description" or "Instructions" ) are excluded from this license. with all rights reserved, unless specifically available for download This notice constitutes a clarification, not a change, to licensing for this design.
I'm not sure how these WILL print - I am sure that they will need support. Experimentation is in order. The dimensions are as accurate from the original part as I could get, but the diameter may need to be squidged a bit for a proper snug fit. Disclaimer- you print and use this part at your own risk.