Two yard panthers and a little good wolf patrol the edge of the Dawnwood forest that is our backyard. We never know what is going to turn up out there so every day is apt to be a learning experience in my backyard laboratory.
Their formal names were slide rules, and folks called them “slip-sticks.” They were literally analog computers. Many years ago, slide rules were de rigeur for engineers and scientists, and especially several generations of high school and college students.
Not only that, but Neil Armstrong used one, according to a recent Wall Street Journal blog.