Related Clues:

• Overgrown, as some walls
• Like Wrigley's walls
• Green on the outside?
• Like college walls
• Unlike rolling stones?
• Like Harvard's walls
• Like some halls or walls
• Like some college buildings' walls
• Like the walls at Wrigley
• Covered with a matted, moist growth, as a forest floor
• What a rolling stone can never be
• Unlike the proverbial rolling stone
• Like old college walls
• Covered with plants, perhaps
• Like many campus buildings