That's just plain cool. I love clashes which reveal themselves in the shallower parts of the opposite devices.
I found it using my loupe. I was searching for extra tree ddr's and then BAM and it was saying "HELLO, HERE I AM " when I flipped it over and saw the trees on the obv my eyes got wide with delight.
ever since you posted the blue ridge parkway you found (at least I believe it was you) I have been on a craze trying to find one. no luck though. I have noticed some polishing lines in the tunnel area. maybe there will be something there.
That's really nice! Usually I see clashes in the fields, so any clash that transfers details inside the portrait is really cool! I can only guess the clashes in the fields were polished out?