Disclaimer: I am not an emtomologist; this is an art/aesthetics post.
I found this when I was doing some chainsaw work in a small oak grove, clearing out dead trees that were in danger of falling onto a home. When I rolled this log and a big chunk of bark peeled off, this design was revealed.
I don’t know much about the insects that made this. It seems that they were some sort of tunneling insects that eat their way through the wood under the bark. Perhaps they were some kind of beetle. And I don’t know if they were what killed this tree, or if they came to feast after it had died.
I also don’t know if there is any scientific reason why these insects ate their tunnels through the wood in this particular pattern, but I appreciated the aesthetics. To me, it looks like they created a pair of songbird wings (ȟupáhu).