Quod Erat Demonstrandum is a 2013 Romanian drama film directed by Andrei Gruzsniczki, starring Sorin Leoveanu and Ofelia Popii.

[1] It won several other awards and was hailed as the best Romanian film of 2014 by several critics, but had fewer than 5000 admissions in its home country, which was seen as a disappointment.

[2] Jay Weissberg of Variety wrote: "Leoveanu and Popii are known for their stage rather than cinematic work, yet they're ideally cast and exhibit zero theatricality.

Black-and-white visuals have a suitable matte range, allowing for gradations in shadow and tone that wouldn't have been possible on digital or color stock.

Cristian Niculescu's production design is uncanny, and Gruzsniczki does a commendable job integrating thesps with their surroundings in a way that feels completely natural.