Above: The anchoring and lacing pattern on the inner face of a wooden book board from 1453.
Not only is it remarkable that the tight “S” twist double cords are still held tightly by the treenail, but I find the almost casual tool marks from a gouge beautiful. They look like they were cut yesterday, although they were protected and covered with a vellum pastedown that became detached at some point in the past. Judging from the splintered wood on the right hand side, it looks as if the hole was drilled first, then the channel cut from left to right. The cuts must have started at the bottom, and worked upwards, ending with what I can imagine was an attempt to clean up the slightly splintered wood. And like most attempts to rectify an error, it only made things worse. A bookbinders mistake from five centuries ago? Notice the split in the board is not caused by the treenail or the two iron nails at the top and bottom of the image, which is often the case.
I’m always impressed by any mechanical object that is still intact and functioning after 557 years.