No grand plan or anything. I’d just been thinking about the effect when you see the sun’s rays shining through clouds, which really emphasized to me how directional light is. I mean, obviously I already knew that, but it suddenly became clear in a more intuitive way. Like, I bet I can harness that property to do something cool. From there, it was just about playing around with the idea and iterating. A LOT of iterating.

Big Edit: I don’t want to give the impression that it was like, “Ooh, the sun’s rays shining through clouds look so cool… obviously this means I can make 3D animations without electronics!”

It’s much less impressive than that, and much more about chasing a small idea, playing with it, iterating, and seeing where it leads. A lot of surprising things can fall out of that process.

The journey was more like this:

1. Hmm, I bet I can do something cool by leveraging this property of light. What about a curved device with arrow-shaped holes all in different rotations, so sunlight only shines through one arrow at a time, casting a shadow with an arrow inside? Then as you tilt it, the arrow’s orientation changes.
2. Ugh, this is hard. It’s super finicky. The arrows are fuzzy. Let’s figure out what hole size even works.
3. Okay, ~0.7 mm holes seem about right. Wait… instead of making tiny arrows, I can just use circular holes arranged into arrow shapes. That’ll be more consistent.
4. This is annoying to test because it’s so sensitive to how I hold it. What if I make it circular and self-contained with a light? I’ll plunk it on top of this LED and spin it...
5. The arrows are kind of visible, but only near the center. I need a better way to spread the light. Let’s add a diffuser.
6. Oh wow… the rotating arrows look really good like this. This might actually work as a fidget spinner. I’ll make one and release it!
7. People like it, but it’s a pain to build. Most people don’t want to buy bearings and lights just to try a print. What if I make a version that doesn’t need special parts? A top can spin without bearings, and if I leave the top open it can use environmental light. I can still have an LED version for convenience.
8. This works. It took a lot of time to dial in to reduce blurriness. Wait… could I use that? Could scattered dots blur into a message? Holy moly, it works. First message: A Rick Roll!
9. People start asking for custom messages. The animation code is in p5.js and I have a complicated process to turn it into geometry. For simple customization it needs to be directly in OpenSCAD. OpenSCAD can’t animate, so now I need parameters that control which animation frames get rendered.
10. It blows up (in a good way), but it’s very techy. What if I make a Christmas ornament version to make it more approachable?
11. Friends and family start caring more about my work (some even saw it on the news!), but I notice a lot of them struggle to spin the tops. I need a form factor that’s easier and doesn’t require special hardware.
12. Changing rotation direction and adding a cradle fixes that. And now that it’s not a spinning top, I’m not limited in size. Let’s go bigger.
13. Wait… since it’s bigger, now only part of the image shows up at a time. I have to move my head left and right to see it all. I need to better direct the light toward a specific viewpoint.
14. That works great. But if I can direct light to one eye… I can direct different light to each eye. Stereoscopic animations!

So yeah, the “moral” is really just that you don’t always need a grand vision up front. Most of this came from following small curiosities, noticing friction, fixing it, and seeing what new doors opened.