In the original script the first scene was supposed to be a bug on a tree but because of the difficulties to find one, the scene was deleted. During the shooting at the park a worm fell down from tree on actor Juán Gómez, the same worm was placed on the tree for the title shot
Due to the short length of the first scene, it was necessary to finish the chess match in a very short amount of time. The match is a replica from one of the shortest chess matches in history.
The second book that Toribio grabs on the second scene is 'Pedro Páramo', one of the greatest works of the Mexican Literature. One of the characters of said novel is called Toribio.
In the scene when Isabel bends down to look for the book and Toribio looks at her bump, it was necessary to push actor Juán Gómez to allow the camera to get the shot.
In the scene when the three characters talk at the park, it was asked to actress Jazmin López to improvise a dialogue while Toribio was watching her. She is actually talking about a joke director Monge told the cast before the shooting of the scene.