These 24" x 24" panels were first used at Gander Mountain's Woodbury, Minnesota store. In the photo above, though both are cast from the same mold, the relative brightness is visibly different, caused by the change in the angle of the light striking the surface.
This view of the panel on the right, above, shows the change from viewing from directly below. It was designed to have the bird flying in a light-toned sky with a darker border to set it off from the light brick. The gander image as well as the mountain image have varying brightness, and change as one walks past while the sky and outer frame remain static.