How to Draw a Perfect Circle (Portuguese: Como Desenhar um Círculo Perfeito) is a 2009 Portuguese drama film directed by Marco Martins and starring Rafael Morais, Daniel Duval, Joana de Verona, Beatriz Batarda, and Albano Jeronimo.
Its plot revolves around a young man named Guilherme and his sister Sofia who grow up sharing experiences and slowly discovering their sexuality.
Guilherme (Rafael Morais) and his sister, Sofia (Joana de Verona), live in their grandmother's mansion, occasionally looked in on by their unconventional mom (Beatriz Batarda).
Their dad Paul (Daniel Duval), an emotionally distant intellectual, returns to Portugal from Paris.
Before this scene, while father and son play Tic-Tac-Toe, Paul remarks that Guilherme can draw a perfect circle but always loses the game.