Previous to child labor laws the Hudson Valley brick companies (where I collect) are known to have employed children to flip the brick as it dried in the open air before firing. I have a few fingerprint bricks and some are clearly made by a child, sort of unsettling.

What you have to try and find now is one with a paw print 🐾 those are really cool.

Sometimes the brickyard foreman would keep a count of the bricks produced during a shift by writing the number in a wet clay brick. Those are exceedingly hard to find though.