How does Rita Dove use imagery in Geometry?

The dominant imagery in the final stanza is sunlight and truth, and the poem does not say that either has suffered from the proving of the theorem. If reality is escaping from geometry here, it isn't being aggressively pursued, indicating that its escape is part of the overall plan. In fact, the final word, "unproven," loops the process back to the opening salvo, "I prove a theorem," indicating that even something as intellectual as a geometric proof is a part of the cycle of nature.