Chain-reaction machines on your desk
Line up parts on a desk and press Start. The ball rolls, the dominoes fall, a trapdoor opens — and the bell rings. A 3D toy box for building contraptions with real physics.
What you can do
Challenge
100 stages across 10 worlds. Ring the bell with as few parts as you can. Clear a world to unlock its main part in Create.
Create
Build your own machines freely. Draw a line with your finger to set up dominoes. 23 kinds of parts, including pendulums, trapdoors and electric lifts, conveyors and fans. Link lifts and conveyors to build machines that never stop.
Community works
Publish your machine, run other people’s creations, like them, and copy them to remix.
Replay & video
Watch the moment the bell rings in slow motion, and save it as a video to share.
Pricing
The app is free, with Worlds 1–7 and the basic parts. Worlds 8–10 and some parts are one-time in-app purchases (no subscription). The app shows ads.