This is the model of the monostable tetrahedron describet in the paper “BUILDING A MONOSTABLE TETRAHEDRON”

Here is an article about it: BME Researchers Confirm a Forty-Year-Old Conjecture by Discovering a New Geometric Body | BME central site

It follows the same dimensions as published in the preprint and is therefore to big for my printer. Furthermore, the original build has an tungsten plate to weigh down one face which I cannot replicate with an fdm printer. 

If you just print this file, it will not tip over accroding to the paper. But if you feel like adding a weight, you can start here: 

This file can be remixed from the attached STEP or from here in Onshape

If you want to print something similar, yet not depending on an added weight, consider a gömböc.