Conway's Game of Life in real life | Hacker News Reader

Conway's Game of Life in real life

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74 pointssurprisetalk20 comments

Cool! This is about an interactive display but initially I thought someone might have managed to make GOL into a physical automaton! Cells could physically sense neighbouring cell states and change their own states.. might still need a global clock to get coherent GOL behaviour but I think that would be fascinating! Also GOL (2,3/3) is only one out of about 1024 possible 2d totalistic CA rules, some of the others have interesting behaviours too and would be fun to be able to explore in the real world :)

I'm sure a clever enough craftsman (not me) could do that, and even avoid the global clock. Each cell could send a "clock tick" to its neighbors whenever it updates its own state, and gradually adjust its tick interval toward the mean tick interval of its current neighbors. (Or maybe just snap quickly to the median tick interval of its neighbors.) After a few ticks all the cells would be synchronized.

To make the thing really "modular," I'd want the communication channels between cells (both the "I'm alive/dead" channel and the "clock tick" channel) to be something like sliding pegs that push into holes on the neighbors and can be sensed either mechanically or optically, not something that requires an electrical current to flow _between_ neighboring cells.

Adafruit sells a 4x4 Game of Life circuit board, which can be connected (permanently, with solder) to other 4x4 boards to make larger boards: https://learn.adafruit.com/game-of-life Having to actually solder it to the other boards makes it not quite what I'm thinking of, but still pretty darn close.

Re counting 2D totalistic CA rules: it could be as many as 2^8 = 256 rules for "I come alive with (1,2,3,4,5,6,7,8) neighbors," times another 256 for "I stay alive with (...) neighbors," for a total of 63356 possible CAs. One _could_ add 16 switches to each cell, and have the cell use whatever rule is encoded by those 16 switches. That feels expensive, though, doesn't it?

Ah yes you're so right, a 'distributed' synchronisation method could work great!

I love the idea of mechanical sensing too! Would be cool if somehow the 3-neighbour 'grow' rule could somehow involve budding off a cell from the (or one of the?) 'parents' and transitions from 1 to 0 (cell death) could actually involve the disassembly of something! : )

Since GOL doesn't consider the self-cell, there are 9 possible values for the 'total' (0 to 8), and since there's both Birth and Survival, that's 18 bits in total, so 2^18 which comes to 262,144 possible rules! That is a LOT more than I thought there were! Cool! - makes me want to explore them again more thoroughly.

I was thinking that "I come alive with 0 neighbors" wouldn't make a sensible rule: it's not reasonable to have the whole universe strobing on and off every clock tick.

But "I stay alive with 0 neighbors" probably makes sense, so okay, multiply what I had said by another factor of 2 and call it 17 bits total. :)

There's probably a way of making these switches for less, if you're willing to trade money for toil and strife. Wind up toys have a very long roll of "wind up spring". 3D print a jig to bend a short piece of that into shape. Use somewhat translucent filament to print the switch. Or use a diffuser/matte thingy from a LCD monitor. I don't know. It'll probably be more expensive in the end but you'll feel good that you did it.

I think you can buy premade LED grid arrays. I would take one of those and overlay one wire per row, one per column, in tension and suspended a few mm apart. You could use a translucent 3d-printed framework to stabilize the wires and have a flexible piece above each junction to act as a button. Not sure how to make it click...

Former discussion (85 comments):

https://news.ycombinator.com/item?id=47434732

I’ve always wanted to do something similar, but with screen printed capacitive sensors on a pcb with a matching led in each sensor.

Much more scalable in cost.

> The switches are around $3 a piece

$3*17*17 = $867 - ouch!

The remark about a touchscreen amused me, since this is essentially a lo-res touchscreen. You can have a super high resolution full color touchscreen for small moneys, but if you want it to be super low res and monochrome you have to pay big moneys and you also have to design and assemble it yourself! In a way this is obvious, but it's also kind of bananas: you can only easily do things that are popular. Then again I suppose there'd be no project if it was easy.

I can't put my finger on it, but there's something very satisfying about seeing his final build, that I think wouldn't be there if it were a touch screen.

If it was a touchscreen, then the whole project could just be replaced by googling Conway’s game of life on an iPad. The physicality is the point.

never underestimate physicality over screens. Look at the backlash to 'big ipad' car dashboards.

this is a ridiculous price.

https://www.alibaba.com/product-detail/12x12mm-Tactile-Switc...

also comes in 15mm squares, rgb led. $0.30 in sub 1k quantities.

Anyone else expecting (fearing) some sort of Stephen King sci-fi game show? Whew - just light bulbs...

I was imagining slime-mold-based logic cells or something

I envisioned something more like a flash mob where people stand in a grid and stand up/sit down based on the state of their cell...

I was really hoping for mechanical clicking and movement.

Also for a glider gun.

is it possible to read out the state of a flipdot display?

with a small amount of additional memory the display could hold the game state and you could manually flip the dots to input the cells.

used to be a big ol' game of life in the seatac airport in the 80s-90s.

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