Related Clues:

• Medium for a picture of Uncle Sam
• Theater sight
• Subway artwork, perhaps
• Diego Rivera art
• Fresco, e.g.
• Painting on moist plaster
• Wall decorations
• Subway artwork, e.g.
• Art on walls
• Rock-concert souvenirs
• Plaster painting
• Sistine Chapel artwork
• Finds at Pompeii
• Picture on a ceiling
• Notices on fences