Many thanks, Drew and Gene, for the fascinating gallery of twist examples, and for the repost of my uncooperative images. Fascinating, too, to see the actual text of the legislation that set the seal of authority on the proof system.
Here are a couple more images of if the Cutler:
Barrel stamps
links[img]https://www.dropbox.com/scl/fi/aged...rlkey=2qml71rv3s1yal5httiqst3d2&dl=0[/img]
Twist pattern
[img]https://www.dropbox.com/scl/fi/a4l3...rlkey=7634o7w05e9gu3s2hgbbuimwc&dl=0[/img]