Spirograph aka My Super Fun Hypotrochoid and Epitrochoid Maker!

Yesterday I pulled out my 1967 almost mint condition Spirograph and sat down to play. I bought this little gem on eBay a few years ago because it was one of my most favorite things to do when I was growing up. I was looking forward to revisiting this old friend since I was certain that as an adult I would be able to eliminate some of the things that frustrated me about it as a child.

As I prepared my work surface I remembered how my uncoordinated child fingers always had trouble coaxing the little map pins out of their container. I discovered that my arthritic adult fingers have the same problem.

As I pinned my ring in place on the official Spirograph corrugated cardboard work surface, I had trouble identifying the holes in the ring that were meant for the pins. There are 4 of them and they're smaller than the other holes, which I still don't know the purpose of. Later I was reminded that it doesn't really matter which holes you stick the map pins into. They will eventually wiggle loose on your last rotation, causing a single misplaced mark on your otherwise perfect geometric creation.

I wonder if the modern versions of Spirograph include a work surface made from something better than corrugated cardboard. Even as a child I can remember thinking it was a poor choice. The corrugation lines sometimes show up on the large Spirograph doodles, not to mention the fact that the pin holes leave behind potholes that your pen will most definitely fall into, causing you to poke an irritating and unwanted hole in your paper.

My vintage Spirograph came complete with the original pens but, alas, the ink didn't survive the decades. I thought I would be really smart and use my Slicci gel pens with the .25mm tips. The tips are so fine they're like writing with a needle which I thought would be perfect for the tiny holes they have to fit into.

The tips did indeed fit nicely in the holes but I discovered that after 3 or 4 passes over the same area, those needle tips acted like little razors and sliced right through the paper.

One of the most frustrating things I remember about my Spirograph was when I got a big misplaced mark across my otherwise pristine creation when the gears accidentally slipped. I was certain this wouldn't be a problem since, as an adult, I would naturally be more careful so that those little plastic teeth stayed perfectly engaged. Okay that didn't happen. The gears slipped and I made a big misplaced mark. The only thing that changed was the string of colorful expletives I let loose when it happened.

I can't recall ever reading the instruction booklet when I was young so I flipped through it to see if maybe there was some helpful information that I might need. There may have been, I'm not sure because the whole thing is written in some kind of mysterious code. I would imagine it's similar to what a crochet pattern looks like to someone who doesn't crochet.

The only helpful information I was able to get from the instruction booklet was that the holes on the rings and on the wheels are numbered and it matters which hole you use and how you line them up if you're going to try to duplicate one of their suggested patterns.

Actually that would have been helpful information if I could actually SEE the tiny clear numbers next to the tiny clear holes on the tiny clear wheels.

And what exactly are the patterns that a Spirograph creates? I usually just call them doodles but according to Wikipedia they are actually "mathematical roulette curves of the variety technically known as hypotrochoids and epitrochoids". Well, heck! What child wouldn't love that?!

But how, exactly, does it work? Thankfully, Wikipedia also offers this pictorial mathematical explanation for how the Spirograph works:

I just love it when things are demystified like that.