How does James Merrill use imagery in Lost in Translation?

Merrill notes the power of art when the speaker's reading of “Palme” triggers a childhood memory. He invests the puzzle with a similar power when the pieces appear to arrange themselves as Mademoiselle and the boy withdraw into the background. The pieces “align themselves with earth or sky” and become “naïve cosmogonists / Whose views clash” or “nomad inlanders” who “Begin to cluster . . . /. . . on the straggler . . . / To form a more sophisticated unit.” The figures in the picture come alive and gaze at each other across clouds.