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After publication of this article, the publisher requested a change to the caption of Figure 25.
The corrected caption is as follows:
Mona Lisa. Leonardo da Vinci, ca. 1503. Oil on wood panel. Although somewhat yellowed, the faint blue haze in the background was inspired by the isoprene-derived blue haze in the hills of the Tuscan countryside, as recorded in Leonardo’s notebooks. (Permission to reuse this image must be obtained from The Louvre.)
