6 pages total, with 15 problems:Step-by-step instructions, answer sheets, cited works, and extra background information. Depending on the age of the students, it may take 30 minutes to teach and an additional 30-90 minutes for the students to complete.This is a form of old trees-and-tents logic puzzles, which probably originated in the Dutch magazine “Brein Brekers.” *On the front of each machine, each dial needs a lever installed in a grid square next to it -- left, right, over or under, not d