This stanza describes a sacrifice. The poet describes the scene making questions to the reader.
In my opinion there are eerie and enigmatic because the reader doesn’t know anything about the story but it’s described as a mysterious event, underlined by the poet’s questions.
They are: “Attic shape”, “Fair Attitude”, “silent form” and “Cold Pastoral”. The beauty of the urn is empathises by “Fair Attitude”, “Attic shape” and “silent form” recall those of the first stanza and “Cold Pastoral” points the functions of art.
It’s recalled when the poet says that silence “dost tease us out of thought”.