By the laws of the game-o-sphere, a computer made from the marbles and metal of alchemy-based puzzler Opus Magnum almost seems like an inevitability. Alchemy and code fan Peer Backhaus has built a - ahem - "Brainfuck interpreter", which is a real computing term and not something I expected to see in my emails when I came into work this morning.
Here's the machine in action, along with the creator's voiceover explanation.
I will not pretend to understand the ins and outs of this, but I get the principles. It's built out of arms that "check" whether an atom is in one place or another. They constantly grab as the machine runs, and if there is an atom to work with, happy days. But if there's no atom to grab, it just spins on and does its job anyway, applying work to empty air. Like a cobbler working on an invisible boot. It's something you can work into the puzzle solutions for the main game. By using this method, a "command token" (basically a molecule with a specific pattern of gold atoms) will "flow" in different directions depending on what gold atoms are present.
I also got an email from Zach Barth of Zachtronics, following up on an interview we've done (look out for that later), in which he mentioned the salt-based machine.
"You asked if anyone had built anything in Opus Magnum that surprised me," he said. "This counts as genuinely surprising."
Open-ended games with lots of moving bits and bobs are programmer fodder. An enterprising fellow once made a 16-bit computer in Minecraft using redstone and that has been followed up with all sorts of monstrous machines.