Spirograph Simulator (2014) | Hacker News Reader

Spirograph Simulator (2014)

nathanfriend.io

139 pointsChuckMcM40 comments

There's a one-line formula that is supposed to capture most of these motions. https://en.wikipedia.org/wiki/Hypotrochoid

What always struck me as interesting is how some of them 'seem' like they're a projection of a surface onto the plane.

Edit: In fact, it would be nice to see a 3d version where the z-axis is the angle of incidence between gears (taking one as reference).

Especially in crazier patterns with gears that are not perfect circles. Too sad this is far in the past: https://www.kickstarter.com/projects/465068187/wild-gears-20...

Note: in the starting position when you open the page, fixed 96, rotating 52. 13 revolutions for the curve to close. 52=4x13=gcd(52,96)x13

See also John Freedman's Cycloid Drawing Machine: https://www.youtube.com/watch?v=ygcGfnVM6Ho

May be slightly off-topic, but for a creative feat using similar mechanisms, see https://www.youtube.com/watch?v=DfznnKUwywQ

While it is in the past, chasing links ( https://www.kickstarter.com/projects/465068187/wild-gears-20... to https://www.facebook.com/WildGearsPlay to http://www.wildgears.com ) brings you to http://www.ponoko.com/showroom/wonders which has the products for sale. Not in the cheap realm, but if one is a hypotrochoid fan, they are out there.

You could also have a 3D spirograph where you rotate an object with an embedded "pen" around the inside of a sphere, say. It draws a 3D shape. This would be very hard to construct, but easy to simulate. Would it give you anything interesting, either as a line drawing or a surface?

I'm not sure, because you would have an additional degree of freedom that needs to be constrained. With a 2D spirograph, you only have one axis of rotation. You can rotate forwards or backwards, but there are no other options. With a 3D object, there are always two possible axes of rotation. The simplest way to handle it would be to only rotate around one axis, but then you are back to just a normal 2D spirograph. There would need to be some non-linear correlation between the rotations, which adds a great deal of complexity.

I think the commenter meant to have it "keep going forward" in the same manner as 2D but with some rotation involved. It's doable.

I once made a tool using this: https://github.com/zhirzh/spirograph-gen

In case you think this is just a toy, have a look at what the professionals do:

https://johncarlosbaez.wordpress.com/2013/12/03/rolling-hypo...

Amazing. Spinors are now my new favourite things. https://en.wikipedia.org/wiki/Spinor#Introduction

After seeing the Spinor 'belt' animations on that page, something in my gut is screaming at me that there's some great use for this phenomenon in EMF power generation.

Without more than skimming, what exactly are they doing with them? It looks just like they're making cool images without any practical purpose.

"I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, and diverting myself in now and then finding a smoother pebble or a prettier shell than ordinary, whilst the great ocean of truth lay all undiscovered before me."

Isaac Newton

This is nice. I wrote a spirograph simulator when I was 14 years old, but of course it didn't have such nice UI (basically it was just a couple of calls of sin(x) and cos(x) in a loop, and some graphics calls, it was much fun nonetheless).

Some ideas:

- Animate the rotation of the gears more smoothly for more realism.

- Add an automatic mode, where the gears keep on moving until it reaches the point when the path starts overlapping itself.

I like physical things and I liked the original Spirograph. But that simulator is so much easier, quicker, and more flexible. You can't even mess up by popping your pen or slipping gears.

Really, there's no reason to own a real Spirograph anymore. You might still want a Spirograph for the same reason you'd want a Curta or an Enigma, i.e., for nostalgia or as a collector's item or to behold the sheer coolness of it. But you or your kid would never play with a Spirograph today, or calculate with a Curta, or encrypt with an Enigma.

I say all this with a bit of sadness because I miss things that I could hold with my hand.

I completely disagree; kids learn a lot by using physical devices, that they won't learn from digital simulations. I think the best we can offer them is a mix of both.

Physical devices develop dexterity and attention to detail. For example, drawing a circle with a compass develops a number of physical abilities. Some kids love the challenge of making neat circles of different sizes, and they'll get something out of using a compass that they'll never get from a digital circle-making tool. And keep in mind, there are different kinds of compasses. There are the pointy-tipped kind that we all think of, and there are flat ruler-types that have a spinning pivot point. Someone who's used these kinds of devices can develop a very concrete understanding of what a radius and a diameter is, among other things. I believe some of the same benefits come from working with a physical spirograph.

Digital simulations allow people to try out many more variations in a short period of time than they could with a physical device. Digging into the code behind these simulations pushes people to understand the mathematical concepts that underlie these tools and patterns.

Our young people can have the best of both worlds; it's our job to help them enjoy the variety of tools that are available to them today.

My daughter (7 years old) still plays with one, but not that often. She still enjoys it.

We have the "Spiral Draw" by Klutz.

>> your kid would never play with a Spirograph today

That just represents AFK parenting. If your 5-8 year old is being babysat by the television or iPad, it is hardly their fault that they aren't experiencing anything hands-on.

“you or your kid would never play with a Spirograph today”

yeah, we would …

My daughter also spent months using one when she was 7-8, not so long ago!

Neat!

A while back I worked on a couple of Common Lisp projects that used the equations behind Spirograph curves to generate animations synced up to music.

The results were really neat: https://vimeo.com/147813490

And the code: https://github.com/jl2/spiro-animation

I also made a GUI version that allows tweaking a bunch of settings: https://github.com/jl2/qt-3d-fft

This reminds me of a similar tool I wrote over a year ago. Uses d3 for SVG features.

It's a bit cryptic about the inputs - can't really recall why I made it in the first place.

demo: https://zhirzh.github.io/spirograph-gen

source: https://github.com/zhirzh/spirograph-gen

original source: https://gist.github.com/zhirzh/27172e92ae95b4167cc1

I love that it will let you mess up and over-draw a line just like the real thing.

Previously at https://news.ycombinator.com/item?id=8698131.

This would be really cool and fun for children if it worked on an iPad

Couldn't stop playing with this, awesome.

Very nice. A couple of suggestions:

- Add ability to move the gear by shifting its position without rotating

- Allow multiple pens

- Shift colors randomly for a pen

- Add elliptical gears

I had one of these as a kid, this brings up fond memories! :)

this spirograph simulator has a really great UI.

countless, otherwise thoughtful, developers consider the User Interface as a mere "finishing touch"

All my childhood nightmares come rushing back.

I loved these as a kid! This brings back memories. I've never thought about the math behind it but maybe I should, this is awesome.

Can you add a button that rotates the gear automatically?

The arrow keys move it. Not quite automatic but easier than the mouse.

INB4 no meta discussions.

How long is it until literally every comment on HN is just "this is unrelated, but x."

Pint taken.

Cheers

In this case, however, it's a fascinating bit of work from Disney Research, and well worth watching.

It makes reading HN impossible.

The difference is that those tangents were interesting and unpredictable, where this one is unsubstantive.

We detached this subthread from https://news.ycombinator.com/item?id=13256464 and marked it off-topic.

You're a little late. The great-grandparent post was long gone from the front page by the time you detached mine.

Reply on news.ycombinator.com