What is the setting of J. B. by Archibald MacLeish?

The setting of the play is a circus tent. In the prologue, two elderly men appear, dressed in the white uniforms of concession vendors. One, Mr. Zuss, is a balloon seller. The other, Nickles, is a popcorn seller. They arrive at the foot of the stage and describe the setting; the stage is heaven, and the audience is earth, they say.