Explicar los últimos dos diálogos del libro Boulevard.

Relief sculpture - images are set against a flat background. a coin is a good example: the inscription, the date, and the figure are slightly raised above a flat surface. the ancient egyptians sometimes carved figures into a flat surface.    pro: they take significantly less time to make and do not require as much tools or skills as free-standingcons: not nearly as realistic, as it is not fully 3-d, and does not have the details that a free-standing one does.freestanding sculptures (also called  carved in the round) are not attached to any  background.  they are 3-dimensional  and fully rendered.

Yes, they totally can. abstract art is art that takes after nothing in particular, therefor making it abstract.