Amoraph, a flower vessel torn from another dimension.
Partly non-orientable and similar in nature to Phamora, but this is a true Klein variant, be it partially.
While the body is traditional, the top loops back on itself and rejoins the body without thinking twice.

This design by Virtox is shared here under the Attribution-NonCommercial-NoDerivs Creative Commons license.

Entry in the Figulo Ceramics Challange, vase category.

Nearly 10cm high, should be fully producible in ceramics.
I have had the pleasure of designing and experimenting with ceramics 3d printing since it was first offered through Shapeways.
I found it to be very addictive and while not as design-flexible as other materials, it is not the fragile creature some think it is.

Based on earlier work, Phamora Ceramics, I made this more traditional version to show (up close) what kind of models are possible with this tech. It's kind of meant as a beginners reference for those wanting more from ceramics but who are afraid that it is not possible.

It should be fully compliant with the stated print-ability rules:
Object density 15%
Bounding box Sum = 276mm
Wall thickness >= 4mm
Curve radii >=2mm