Final answer:
The word 'obscure' fills the blank correctly, implying that the dark shadows conceal the details of the mural on the wall, altering its appearance and mood, a concept supported by literary and artistic examples.
Step-by-step explanation:
The dark shadows obscure the lovely mural painting on the brick wall. In various literary contexts, shadows often enhance the mood or theme of a scene. As seen in the provided texts, shadows can transform the appearance of objects, create contrast, and even affect the emotional tone. For example, in painting, as mentioned about the works of Constable and Delacroix, shadows composed of strands of color can revolutionary change the representation of a mural, creating a dynamic interplay of light and dark, known as chiaroscuro. Furthermore, shadows can add a sense of foreboding or mystery, and interrupt the visibility of things, as suggested in the various examples, which point to the different effects of shadows, from obscuring to highlighting features.