"A modern and minimalist book cover design for Sis (La niebla) by Miguel de Unamuno. The cover should feature a symbolic pencil sketch of the main characters or key events from the novel. The drawing should be simple yet powerful, with the faces or silhouettes of the characters reflecting the existential and identity-seeking themes of the novel. The atmosphere of Sis and Unamuno's philosophical depth can be conveyed through a sense of ambiguity, fog, and indecisiveness in the sketch. The design should avoid the use of too many colors, focusing primarily on black and white tones or shades of gray. A minimalist approach is crucial, with the drawing positioned at the center, while the background should remain simple and uncluttered." --ar 3:4