What is Impossible Machines?
Impossible Machines is a free interactive experiment in your browser. On a 3D workbench you place a source, such as a crank or a weight, and a target, such as a bell or a door. Then you show what you want to happen, and a working mechanism appears between cause and effect to make it happen.
Move the target, add an obstacle or change the shape, and the machine redesigns itself around it. A constraint solver works out the connection behind the scenes. There are challenges such as making a detour, beating the brake and a guided turn, plus a freeform bench to play on.
It was made by @bhaprayan as a thought experiment about declarative programming for the physical world: you describe the result you want, not the steps to get there. It was a Show HN in October 2026.
Main Features
- A 3D workbench with sources, obstacles and sinks
- Show the effect you want and a mechanism appears
- Machines that rebuild around obstacles
- Challenges plus a freeform bench
- Parts like cranks, weights, blocks, brakes, guides, bells and doors
- Works on desktop, and on phones held sideways
How to Get Started with Impossible Machines
- Open impossiblemachines.xyz in a browser with WebGL.
- Tap the bell, or another target, to show what you want it to do.
- Watch the mechanism appear between the source and the target.
- Add obstacles or move parts and see the machine adapt.
- Try the Challenges or the freeform bench.
Impossible Machines Pricing
Impossible Machines is free in your browser, with no account.
Who Should Use It?
- People who love Rube Goldberg machines
- Programmers curious about declarative ideas
- Students interested in mechanics and engineering
- Anyone who enjoys a satisfying physics toy
Impossible Machines Alternatives
- Line Riderdraw a track and watch the rider go
- Sandspiela falling-sand physics toy
- Genetic Carswatch cars evolve to drive further
Frequently Asked Questions
Is Impossible Machines free?
Yes. It is free in your browser, with no account.
How does Impossible Machines work?
You show the effect you want, such as ringing a bell, and a constraint solver builds a mechanism that connects the source to it.
Why does Impossible Machines not load?
It needs WebGL. Try a current browser with hardware acceleration switched on.
Can I play Impossible Machines on a phone?
Yes, but it works best in landscape, where there is room to explore the mechanism.