Mateo's painting is difficult and complex to execute, as most of the pieces are made with a mixed media technique, in which he incorporates corrugated cardboard, paper or canvas as a collage, giving the work a certain visual three-dimensionality. In fact, it is like a kind of game between the creator and the viewer, since a real element can appear anywhere - the collage - to replace what is painted.

Emotions, feelings, experiences, loves and passions are in each of his paintings. This is the true reality of the painter: to reflect what he feels at every moment and then to express it in the painting, and also with the added circumstance that he can do it whenever he wishes.