Acer glabrum Torr.
Silhouette of nearer leaf against backlit leaf, viewed from near the trunk.

Image used to be posted on Flikr, where it was #6 in popularity and #4 in "interestingness" among my few images there.
Earned a ribbon in the April 2013 Portneuf Valley Photographic Society's annual judged show at the Pocatello Art Center,
hung there for a month, and hung for two months in the Marshall Public Library in Pocatello. It now resides at the house
of a friend who liked it enough to purchase it. Woohoo--as a result I got to see it on a weekly basis for a few months.