Improved Margolus critter 3D printed tiles

pcallahan · Post by **pcallahan** » May 15th, 2025, 1:15 am

After a year of experience with 3D printing, I went back to the question of implementing Margolus Critters with layered tiles.

I think the results are more usable than my previous implementation, though I may be one of the few people who ever print them and try them out. Here's my printables page: https://www.printables.com/model/127740 ... ther-tiles

My previous effort can be found here: viewtopic.php?f=7&t=3884&p=182137#p181692 and that thread contains the ideas behind it.

The 6 tiles are shown below, along with some optional parts. The tiles have holes that fit layer by layer and force alternating position, as needed for a block CA.

: 20250514_211916.jpg (1.22 MiB) Viewed 1821 times

The optional parts are shown on the bottom row. In left to right order they are:

A thin cover over the holes to make each layer less visually complex and more readable.
A base tile that can hold the first layer together. The bumps are designed to fit in either hole.
A cap for pushing resistant tiles without the bumps digging into your thumb. It's not strictly necessary but can help if you are doing a lot.

I was able to print in two colors by switching filament in the middle of printing. It makes a big difference visually and in my opinion is worth the effort, but you don't have to.

This picture illustrates five layers of tiles with a simulated background. The real tiles have covers on them.

: image1.jpg (795.02 KiB) Viewed 1821 times

Following these images left to right and down to the final one on the bottom.

Step 0 of the critter. It consists of the 4 triangles with dots against a background of 0 (semicircle).
Step 1, after placing a layer on top. This inverts the background to 1 (dotted triangle). The critter cells are 4 semicircles without dots.
Step 2, where we have returned to the 0 (semicircle) background. The critter again consists of 4 dotted triangles.
Step 3. Again, the background is 1 (triangles) and the critter consists of four semicircles.
Step 4. Finally, we have restored the shape of the original critter, against the same background, but it is displaced vertical by one tile position (two cells)

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Here's a real photo of the tiles snapped together, this time without covers.

: 20250501_211041.jpg (761.14 KiB) Viewed 1821 times

I added the covers after really struggling to read what I was supposed to see here.