Moebius heart

Moebius ribbon-shaped heart with two turns

Printable without supports (upside down), but needs brims (and some glue especially with pla).

Two versions:
As sculpture. 12 cm high.
It has a cut in the upper part (to improve the adherence) and another in the lower part (to serve as base once printed). It is convenient to add infill in the lower part to improve stability.

As pendant. 5 cm high.
The knot is closed, so you can add a string or chain to hang it. Also with a ring it can be used as a key chain.
It only has the cut in the upper part.

I have included 3mf as examples. 
In the sculpture there is a gradual increase of the infill using modifiers (instead of layer height, since it works if the model is scaled) to give weight to the base and make the change of opacity not very noticeable (if the filament is translucent), although with 3 perimeters surely it is not appreciated. It is also disabled "Ensure vertical shell thickness". 

You can scale the sculpture to make it larger (there is a 3mf version with forced supports in the initial layers, just in case) or you can make the pendant smaller, so it can even be worn as an earring.

There is a full version of both (without cuts) to allow further customization.  Also a lowpoly version and a lowres version just for quick previs.