The marks in "Holzwege," which I posted Tuesday on my blotcomics blog, are based on this photograph I took of a fallen tree, in a park near my house:
Nature writes asemically, doesn't it?
Here are a couple more photographs
of the same tree trunk:
And here are a few more
photographs I took on the same walk:
As for the source for the title of "Holzwege,"
I'll let you figure that one out by yourselves.