I know the answer because I've actually done this with real bolts (out of boredom — before I knew Martin Gardner had a puzzle about it). Likewise I also know t

I know the answer because I've actually done this with real bolts (out of boredom — before I knew Martin Gardner had a puzzle about it). Likewise I also know the answer to which direction the spool rolls if you set it on a table and slowly pull on the thread.